| Records |
| Author |
Haruta, N.; Kitagawa, T. |
| Title |
Time-resolved UV resonance Raman investigation of protein folding using a rapid mixer: characterization of kinetic folding intermediates of apomyoglobin |
Type |
Journal Article |
| Year |
2002 |
Publication |
Biochemistry |
Abbreviated Journal |
Biochemistry |
| Volume |
41 |
Issue |
21 |
Pages |
6595-6604 |
Keywords  |
Animals; Apoproteins/*chemistry; Circular Dichroism; Holoenzymes/chemistry; Horses; Hydrochloric Acid/chemistry; Hydrogen-Ion Concentration; Imidazoles/chemistry; Kinetics; Models, Molecular; Myoglobin/*chemistry; Peptide Fragments/chemistry; *Protein Folding; Protein Structure, Secondary; Spectrum Analysis, Raman/*methods; Tryptophan/*chemistry; Ultraviolet Rays; Whales |
| Abstract |
The 244-nm excited transient UV resonance Raman spectra are observed for the refolding intermediates of horse apomyoglobin (h-apoMb) with a newly constructed mixed flow cell system, and the results are interpreted on the basis of the spectra observed for the equilibrium acid unfolding of the same protein. The dead time of mixing, which was determined with the appearance of UV Raman bands of imidazolium upon mixing of imidazole with acid, was 150 micros under the flow rate that was adopted. The pH-jump experiments of h-apoMb from pH 2.2 to 5.6 conducted with this device demonstrated the presence of three folding intermediates. On the basis of the analysis of W3 and W7 bands of Trp7 and Trp14, the first intermediate, formed before 250 micros, involved incorporation of Trp14 into the alpha-helix from a random coil. The frequency shift of the W3 band of Trp14 observed for this process was reproduced with a model peptide of the A helix when it forms the alpha-helix. In the second intermediate, formed around 1 ms after the start of refolding, the surroundings of both Trp7 and Trp14 were significantly hydrophobic, suggesting the formation of the hydrophobic core. In the third intermediate appearing around 3 ms, the hydrophobicity was relaxed to the same level as that of the pH 4 equilibrium intermediate, which was investigated in detail with the stationary state technique. The change from the third intermediate to the native state needs more time than 40 ms, while the appearance of the native spectrum after the mixing of the same solutions was confirmed separately. |
| Address |
School of Mathematical and Physical Sciences, The Graduate University for Advanced Studies, Myodaiji, Okazaki 444-8585, Japan |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0006-2960 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:12022863 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3785 |
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| Author |
Polverini, E.; Cugini, G.; Annoni, F.; Abbruzzetti, S.; Viappiani, C.; Gensch, T. |
| Title |
Molten globule formation in apomyoglobin monitored by the fluorescent probe Nile Red |
Type |
Journal Article |
| Year |
2006 |
Publication |
Biochemistry |
Abbreviated Journal |
Biochemistry |
| Volume |
45 |
Issue |
16 |
Pages |
5111-5121 |
| Keywords |
Animals; Apoproteins/*chemistry/*metabolism; Binding Sites; Computer Simulation; Fluorescent Dyes/analysis; Horses; Hydrogen-Ion Concentration; Models, Molecular; Myoglobin/*chemistry/*metabolism; Oxazines/*analysis/chemistry; Protein Binding; Protein Folding; Protein Structure, Tertiary |
| Abstract |
The interaction of nile red (NR) with apomyoglobin (ApoMb) in the native (pH 7) and molten globule (pH 4) states was investigated using experimental and computational methods. NR binds to hydrophobic locations in ApoMb with higher affinity (K(d) = 25 +/- 5 microM) in the native state than in the molten globule state (K(d) = 52 +/- 5 microM). In the molten globule state, NR is located in a more hydrophobic environment. The dye does not bind to the holoprotein, suggesting that the binding site is located at the heme pocket. In addition to monitoring steady-state properties, the fluorescence emission of NR is capable of tracking submillisecond, time-resolved structural rearrangements of the protein, induced by a nanosecond pH jump. Molecular dynamics simulations were run on ApoMb at neutral pH and at pH 4. The structure obtained for the molten globule state is consistent with the experimentally available structural data. The docking of NR with the crystal structure shows that the ligand binds into the binding pocket of the heme group, with an orientation bringing the planar ring system of NR to overlap with the position of two of the heme porphyrin rings in Mb. The docking of NR with the ApoMb structure at pH 4 shows that the dye binds to the heme pocket with a slightly less favorable binding energy, in keeping with the experimental K(d) value. Under these conditions, NR is positioned in a different orientation, reaching a more hydrophobic environment in agreement with the spectroscopic data. |
| Address |
Dipartimento di Fisica, Universita degli Studi di Parma, Viale G. P. Usberti 7/A, 43100 Parma, Italy |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0006-2960 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:16618100 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3763 |
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| Author |
Saigo, S. |
| Title |
A transient spin-state change during alkaline isomerization of ferricytochrome c |
Type |
Journal Article |
| Year |
1981 |
Publication |
Journal of Biochemistry |
Abbreviated Journal |
J Biochem (Tokyo) |
| Volume |
89 |
Issue |
6 |
Pages |
1977-1980 |
| Keywords |
Animals; *Cytochrome c Group; Horses; Hydrogen-Ion Concentration; Isomerism; Kinetics; Myocardium/enzymology; Oxidation-Reduction; Spectrophotometry |
| Abstract |
Kinetic difference spectra during the alkaline isomerization of ferricytochrome c were obtained by the pH-jump method in the range of 540 to 655 nm. The spectrum of the transient intermediate, which appears during the course of the isomerization, was reproduced from the spectra. The intermediate showed an intense absorption band at 600 nm, indicating that it is a high spin or mixed spin species. This is in contrast to the stable neutral and alkaline forms which are low spin species. The transient spin-state change during the isomerization was also observed upon rapid oxidation of ferrocytochrome c at alkaline pH. |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0021-924X |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:6270075 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3808 |
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| Author |
Dyson, H.J.; Beattie, J.K. |
| Title |
Spin state and unfolding equilibria of ferricytochrome c in acidic solutions |
Type |
Journal Article |
| Year |
1982 |
Publication |
The Journal of Biological Chemistry |
Abbreviated Journal |
J Biol Chem |
| Volume |
257 |
Issue |
5 |
Pages |
2267-2273 |
| Keywords |
Animals; *Cytochrome c Group; Electron Spin Resonance Spectroscopy; Heme; Horses; Hydrogen-Ion Concentration; Kinetics; Ligands; Myocardium; Protein Binding; Protein Conformation; Spectrophotometry; Temperature |
| Abstract |
Equilibrium, stopped flow, and temperature-jump spectrophotometry have been used to identify processes in the unfolding of ferricytochrome c in acidic aqueous solutions. A relaxation occurring in approximately 100 microseconds involves perturbation of a spin-equilibrium between two folded conformers of the protein with methionine-80 coordinated or dissociated from the heme iron. The protein unfolds more slowly, in milliseconds, with dissociation and protonation of histidine-18. These two transitions appear cooperative in equilibrium measurements at low (0.01 M) ionic strength, but are separated at higher (0.10 M) ionic strength. They are resolved under both conditions in the dynamic measurements. The spin-equilibrium description permits a unified explanation of a number of properties of ferricytochrome c in acidic aqueous solutions. |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0021-9258 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:6277891 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3807 |
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| Author |
Abbruzzetti, S.; Viappiani, C.; Small, J.R.; Libertini, L.J.; Small, E.W. |
| Title |
Kinetics of histidine deligation from the heme in GuHCl-unfolded Fe(III) cytochrome C studied by a laser-induced pH-jump technique |
Type |
Journal Article |
| Year |
2001 |
Publication |
Journal of the American Chemical Society |
Abbreviated Journal |
J Am Chem Soc |
| Volume |
123 |
Issue |
27 |
Pages |
6649-6653 |
| Keywords |
Animals; *Bacterial Proteins; Cytochrome c Group/*chemistry; Guanidine/*chemistry; Heme/*chemistry; Histidine/*chemistry; Horses; Hydrogen-Ion Concentration; Kinetics; *Lasers; Ligands; Protein Folding |
| Abstract |
We have developed an instrumental setup that uses transient absorption to monitor protein folding/unfolding processes following a laser-induced, ultrafast release of protons from o-nitrobenzaldehyde. The resulting increase in [H(+)], which can be more than 100 microM, is complete within a few nanoseconds. The increase in [H(+)] lowers the pH of the solution from neutrality to approximately 4 at the highest laser pulse energy used. Protein structural rearrangements can be followed by transient absorption, with kinetic monitoring over a broad time range (approximately 10 ns to 500 ms). Using this pH-jump/transient absorption technique, we have examined the dissociation kinetics of non-native axial heme ligands (either histidine His26 or His33) in GuHCl-unfolded Fe(III) cytochrome c (cyt c). Deligation of the non-native ligands following the acidic pH-jump occurs as a biexponential process with different pre-exponential factors. The pre-exponential factors markedly depend on the extent of the pH-jump, as expected from differences in the pK(a) values of His26 and His33. The two lifetimes were found to depend on temperature but were not functions of either the magnitude of the pH-jump or the pre-pulse pH of the solution. The activation energies of the deligation processes support the suggestion that GuHCl-unfolded cyt c structures with non-native histidine axial ligands represent kinetic traps in unfolding. |
| Address |
Dipartimento di Fisica, Universita di Parma, Istituto Nazionale per la Fisica della Materia, 43100 Parma, Italy |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0002-7863 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:11439052 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3788 |
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| Author |
Nicol, C.J.; Davidson, H.P.D.; Harris, P.A.; Waters, A.J.; Wilson, A.D. |
| Title |
Study of crib-biting and gastric inflammation and ulceration in young horses |
Type |
Journal Article |
| Year |
2002 |
Publication |
The Veterinary record |
Abbreviated Journal |
Vet. Rec. |
| Volume |
151 |
Issue |
22 |
Pages |
658-662 |
| Keywords |
Animal Husbandry/methods; Animals; Antacids/therapeutic use; *Behavior, Animal; Diet/veterinary; Endoscopy, Gastrointestinal/veterinary; Feces/chemistry; Female; Gastritis/diet therapy/physiopathology/*veterinary; Horse Diseases/diet therapy/*physiopathology/psychology; Horses; Hydrogen-Ion Concentration; Male; Random Allocation; Stereotyped Behavior/*physiology; Stomach Ulcer/diet therapy/physiopathology/*veterinary; Treatment Outcome; Weaning |
| Abstract |
Nineteen young horses that had recently started to perform the stereotypy of crib-biting were compared with 16 non-stereotypic horses for 14 weeks. After initial observations of their behaviour and an endoscopic examination of the condition of their stomachs, the horses were randomly allocated to a control or an antacid diet At the start of the trial, the stomachs of the crib-biting foals were significantly more ulcerated and inflamed than the stomachs of the normal foals. In addition, the faecal pH of the crib-biting foals (6.05) was significantly lower than that of the normal foals (6.58). The antacid diet resulted in a significant improvement in the condition of the horses' stomachs. The crib-biting behaviour declined in most of the foals, regardless of their diet, but tended to decline to a greater extent in the foals on the antacid diet. |
| Address |
Department of Clinical Veterinary Science, University of Bristol, Langford House, Bristol BS40 5DU |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0042-4900 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:12498408 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
83 |
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| Author |
Ziegler, W.H. |
| Title |
[Endocrinological studies in arterial hypertension. Search for phaeochromocytoma] |
Type |
Journal Article |
| Year |
1976 |
Publication |
Schweizerische Medizinische Wochenschrift |
Abbreviated Journal |
Schweiz Med Wochenschr |
| Volume |
106 |
Issue |
34 |
Pages |
1148-1150 |
| Keywords |
Angiography; Blood Volume; Catecholamines/urine; Glucagon/diagnostic use; Histamine/diagnostic use; Humans; Hydrogen-Ion Concentration; Hypertension/*etiology; Methods; Pheochromocytoma/*complications/diagnosis; Tyramine/diagnostic use |
| Abstract |
Elevated urinary catecholamines and their metabolites are the only findings which confirm the presence of pheochromocytoma. This examination is of particular interest if carried out in urine produced after spontaneous hypertensive episodes. Pharmacologic tests when carried out under standard conditions have proven to be a reliable aid in cases of suspected pheochromocytoma. Roentgenographic studies, determination of local plasma catecholamine concentrations and blood volume control should be undertaken in these patients before surgical procedure. |
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Place of Publication |
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| Language |
German |
Summary Language |
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Original Title |
Endokrinologische Untersuchungen bei arterieller Hypertonie. Suche nach Phaochromozytom |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0036-7672 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:12561 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
4047 |
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| Author |
Hillidge, C.J.; Lees, P. |
| Title |
Cardiac output in the conscious and anaesthetised horse |
Type |
Journal Article |
| Year |
1975 |
Publication |
Equine veterinary journal |
Abbreviated Journal |
Equine Vet J |
| Volume |
7 |
Issue |
1 |
Pages |
16-21 |
| Keywords |
Anesthesia, Inhalation/*veterinary; Animals; Carbon Dioxide/blood; *Cardiac Output/veterinary; *Consciousness; Electrocardiography/veterinary; Ether, Ethyl; Female; Halothane; Heart Rate; Heart Ventricles/physiology; Horses/*physiology; Hydrogen-Ion Concentration; Male; Oxygen/blood; Posture |
| Abstract |
Cardiac output in the horse was measured before and at predetermined times during 2-hour periods of thiopentone-halothane and thiopentone-diethyl ether anaesthesia. Left ventricular stroke volume was decreased to a similar extent during anaesthesia with each volatile agent, but a greater reduction in cardiac output occurred during halothane anaesthesia. This finding reflected the differing effects of halothane and ether on heart rate, a slight bradycardia occurring with the former agent while ether produced a small degree of tachycardia. The latter effect was attributed to enhanced sympathoadrenal activity. Changes in cardiac output and stroke volume were considered in relation to other factors, including arterial blood pH and tensions of oxygen and carbon dioxide. Positive correlations between some of these variables and cardiac function were established. With both volatile agents the reductions in stroke volume and cardiac output were related to the duration of anaesthesia, being greatest during the early stages. Possible reasons for the tendency of stroke volume and cardiac output to return towards control levels are discussed. |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0425-1644 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:234842 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
102 |
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| Author |
Hirota, S.; Suzuki, M.; Watanabe, Y. |
| Title |
Hydrophobic effect of trityrosine on heme ligand exchange during folding of cytochrome c |
Type |
Journal Article |
| Year |
2004 |
Publication |
Biochemical and Biophysical Research Communications |
Abbreviated Journal |
Biochem Biophys Res Commun |
| Volume |
314 |
Issue |
2 |
Pages |
452-458 |
| Keywords |
Amino Acids/chemistry; Animals; Cytochromes c/*chemistry; Heme/*chemistry; Histidine/chemistry; Horses; Hydrogen-Ion Concentration; Kinetics; Ligands; Myocardium/chemistry; Peptides/chemistry; Protein Folding; Spectrophotometry; Spectrum Analysis, Raman; Tyrosine/*analogs & derivatives/*chemistry |
| Abstract |
Effect of a hydrophobic peptide on folding of oxidized cytochrome c (cyt c) is studied with trityrosine. Folding of cyt c was initiated by pH jump from 2.3 (acid-unfolded) to 4.2 (folded). The Soret band of the 2-ms transient absorption spectrum during folding decreased its intensity and red-shifted from 397 to 400 nm by interaction with trityrosine, whereas tyrosinol caused no significant effect. The change in the transient absorption spectrum by interaction with trityrosine was similar to that obtained with 100 mM imidazole, which showed that the population of the intermediate His/His coordinated species increased during folding of cyt c by interaction with trityrosine. The absorption change was biphasic, the fast phase (82+/-9s(-1)) corresponding to the transition from the His/H(2)O to the His/Met coordinated species, whereas the slow phase (24+/-3s(-1)) from His/His to His/Met. By addition of trityrosine, the relative ratio of the slow phase increased, due to increase of the His/His species at the initial stage of folding. According to the resonance Raman spectra of cyt c, the high-spin 6-coordinate and low-spin 6-coordinate species were dominated at pH 2.3 and 4.2, respectively, and these species were not affected by addition of trityrosine. These results demonstrated that the His/His species increased by interaction with trityrosine at the initial stage of cyt c folding, whereas the heme coordination structure was not affected by trityrosine when the protein was completely unfolded or folded. Hydrophobic peptides thus may be useful to study the effects of hydrophobic interactions on protein folding. |
| Address |
Department of Physical Chemistry, Kyoto Pharmaceutical University, Yamashina-ku, 607-8414 Kyoto, Japan. hirota@mb.kyoto-phu.ac.jp |
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Place of Publication |
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Editor |
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English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0006-291X |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:14733927 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3777 |
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| Author |
Saigo, S. |
| Title |
Kinetic and equilibrium studies of alkaline isomerization of vertebrate cytochromes c |
Type |
Journal Article |
| Year |
1981 |
Publication |
Biochimica et Biophysica Acta |
Abbreviated Journal |
Biochim Biophys Acta |
| Volume |
669 |
Issue |
1 |
Pages |
13-20 |
| Keywords |
Amino Acid Sequence; Animals; Cytochrome c Group/*metabolism; Dogs; Hydrogen-Ion Concentration; Isomerism; Kinetics; Vertebrates/metabolism |
| Abstract |
Equilibria and kinetics of alkaline isomerization of seven ferricytochromes c from vertebrates were studied by pH-titration and pH-jump methods in the pH region of 7-12. In the equilibrium behavior, no significant difference was detected among the cytochromes c, whereas marked differences in the kinetic behavior were observed. According to the kinetic behavior of the isomerization, the cytochromes c examined fall into three classes: Group I (horse, sheep, dog and pigeon cytochromes c), Group II (tuna and bonito cytochromes c) and Group III (rhesus monkey cytochrome c). The kinetic results are interpreted in terms of the sequential scheme: Neutral form in equilibrium with fast Transient form in equilibrium with slow Alkaline form where the neutral and alkaline forms are the species stable at neutral and alkaline pH, respectively, and the transient form is a kinetic intermediate. From comparison of the primary sequences of the seven cytochromes c and the classification of these cytochromes c, it is concluded that the amino acid substitution Phe/Tyr at the 46-th position has a major influence on the kinetic behavior. In Group II and III cytochromes c, the ionization of Tyr-46 is suggested to bring about loosening of the heme crevice and thus facilitate the ligand replacement involved in the isomerization. |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0006-3002 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:6271238 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
3871 |
| Permanent link to this record |
