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Measuring denatured state energetics: deviations from random coil behavior and implications for the folding of iso-1-cytochrome c.
J Mol Biol. 2000 Feb 11; 296(1):217-28.JM

Abstract

The changes in the free energy of the denatured state of a set of yeast iso-1-cytochrome c variants with single surface histidine residues have been measured in 3 M guanidine hydrochloride. The thermodynamics of unfolding by guanidine hydrochloride is also reported. All variants have decreased stability relative to the wild-type protein. The free energy of the denatured state was determined in 3 M guanidine hydrochloride by evaluating the strength of heme-histidine ligation through determination of the pK(a) for loss of histidine binding to the heme. The data are corrected for the presence of the N-terminal amino group which also ligates to the heme under similar solution conditions. Significant deviations from random coil behavior are observed. Relative to a variant with a single histidine at position 26, residual structure of the order of -1.0 to -2.5 kcal/mol is seen for the other variants studied. The data explain the slower folding of yeast iso-1-cytochrome c relative to the horse protein. The greater number of histidines and the greater strength of ligation are expected to slow conversion of the histidine-misligated forms to the obligatory aquo-heme intermediate during the ligand exchange phase of folding. The particularly strong association of histidine residues at positions 54 and 89 may indicate regions of the protein with strong energetic propensities to collapse against the heme during early folding events, consistent with available data in the literature on early folding events for cytochrome c.

Authors+Show Affiliations

Department of Chemistry and Biochemistry, University of Denver, 2190 East Iliff Avenue, Denver, CO 80208-2436, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

10656828

Citation

Godbole, S, et al. "Measuring Denatured State Energetics: Deviations From Random Coil Behavior and Implications for the Folding of Iso-1-cytochrome C." Journal of Molecular Biology, vol. 296, no. 1, 2000, pp. 217-28.
Godbole S, Hammack B, Bowler BE. Measuring denatured state energetics: deviations from random coil behavior and implications for the folding of iso-1-cytochrome c. J Mol Biol. 2000;296(1):217-28.
Godbole, S., Hammack, B., & Bowler, B. E. (2000). Measuring denatured state energetics: deviations from random coil behavior and implications for the folding of iso-1-cytochrome c. Journal of Molecular Biology, 296(1), 217-28.
Godbole S, Hammack B, Bowler BE. Measuring Denatured State Energetics: Deviations From Random Coil Behavior and Implications for the Folding of Iso-1-cytochrome C. J Mol Biol. 2000 Feb 11;296(1):217-28. PubMed PMID: 10656828.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Measuring denatured state energetics: deviations from random coil behavior and implications for the folding of iso-1-cytochrome c. AU - Godbole,S, AU - Hammack,B, AU - Bowler,B E, PY - 2000/2/5/pubmed PY - 2000/3/18/medline PY - 2000/2/5/entrez SP - 217 EP - 28 JF - Journal of molecular biology JO - J Mol Biol VL - 296 IS - 1 N2 - The changes in the free energy of the denatured state of a set of yeast iso-1-cytochrome c variants with single surface histidine residues have been measured in 3 M guanidine hydrochloride. The thermodynamics of unfolding by guanidine hydrochloride is also reported. All variants have decreased stability relative to the wild-type protein. The free energy of the denatured state was determined in 3 M guanidine hydrochloride by evaluating the strength of heme-histidine ligation through determination of the pK(a) for loss of histidine binding to the heme. The data are corrected for the presence of the N-terminal amino group which also ligates to the heme under similar solution conditions. Significant deviations from random coil behavior are observed. Relative to a variant with a single histidine at position 26, residual structure of the order of -1.0 to -2.5 kcal/mol is seen for the other variants studied. The data explain the slower folding of yeast iso-1-cytochrome c relative to the horse protein. The greater number of histidines and the greater strength of ligation are expected to slow conversion of the histidine-misligated forms to the obligatory aquo-heme intermediate during the ligand exchange phase of folding. The particularly strong association of histidine residues at positions 54 and 89 may indicate regions of the protein with strong energetic propensities to collapse against the heme during early folding events, consistent with available data in the literature on early folding events for cytochrome c. SN - 0022-2836 UR - https://www.unboundmedicine.com/medline/citation/10656828/Measuring_denatured_state_energetics:_deviations_from_random_coil_behavior_and_implications_for_the_folding_of_iso_1_cytochrome_c_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022-2836(99)93454-X DB - PRIME DP - Unbound Medicine ER -