Ligand binding and protein relaxation in heme proteins: a room temperature analysis of nitric oxide geminate recombination Petrich, Jacob Lambry, J.-C. Petrich, Jacob Kuczera, K. Karplus, M. Poyart, C. Martin, J.-L.
dc.contributor.department Chemistry 2018-02-17T09:37:29.000 2020-06-30T01:23:01Z 2020-06-30T01:23:01Z Tue Jan 01 00:00:00 UTC 1991 1991-04-01
dc.description.abstract <p>Ultrafast absorption spectroscopy is used to study heme-NO recombination at room temperature in aqueous buffer on time scales where the ligand cannot leave its cage environment. While a single barrier is observed for the cage recombination of NO with heme in the absence of globin, recombination in hemoglobin and myoglobin is nonexponential. Examination of hemoglobin with and without inositol hexaphosphate points to proximal constraints as important determinants of the geminate rebinding kinetics. Molecular dynamics simulations of myoglobin and heme-imidazole subsequent to ligand dissociation were used to investigate the transient behavior of the Fe-proximal histidine coordinate and its possible involvement in geminate recombination. The calculations, in the context of the absorption measurements, are used to formulate a distinction between nonexponential rebinding that results from multiple protein conformations (substates) present at equilibrium or from nonequilibrium relaxation of the protein triggered by a perturbation such as ligand dissociation. The importance of these two processes is expected to depend on the time scale of rebinding relative to equilibrium fluctuations and nonequilibrium relaxation. Since NO rebinding occurs on the picosecond time scale of the calculated myoglobin relaxation, a time-dependent barrier is likely to be an important factor in the observed nonexponential kinetics. The general implications of the present results for ligand binding in heme proteins and its time and temperature dependence are discussed. It appears likely that, at low temperatures, inhomogeneous protein populations play an important role and that as the temperature is raised, relaxation effects become significant as well.</p>
dc.description.comments <p>Reprinted (adapted) with permission from <em>Biochemistry</em> 30 (1991): 3975, doi: <a href="" target="_blank">10.1021/bi00230a025</a>. Copyright 1991 American Chemical Society.</p>
dc.format.mimetype application/pdf
dc.identifier archive/
dc.identifier.articleid 1850
dc.identifier.contextkey 7967479
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath chem_pubs/803
dc.language.iso en
dc.source.bitstream archive/|||Sat Jan 15 02:05:17 UTC 2022
dc.source.bitstream archive/|||Sat Jan 15 02:05:19 UTC 2022
dc.source.uri 10.1021/bi00230a025
dc.subject.disciplines Chemistry
dc.subject.keywords hemoprotein
dc.subject.keywords nitrogen oxide
dc.subject.keywords ligand binding
dc.subject.keywords heme
dc.subject.keywords hemeproteins
dc.subject.keywords hemoglobuins
dc.subject.keywords kinetics
dc.subject.keywords mathematics
dc.subject.keywords myoglobin
dc.subject.keywords nitric oxide
dc.subject.keywords phytic acid
dc.title Ligand binding and protein relaxation in heme proteins: a room temperature analysis of nitric oxide geminate recombination
dc.type article
dc.type.genre article
dspace.entity.type Publication
relation.isAuthorOfPublication 563e8d72-b6e9-4617-91c0-589d263e00fc
relation.isOrgUnitOfPublication 42864f6e-7a3d-4be3-8b5a-0ae3c3830a11
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