Journal article
Dissection of the pathway of molecular recognition by calmodulin
Biochemistry (Easton), Vol.41(8), pp.2599-2608
02/26/2002
DOI: 10.1021/bi011818f
PMID: 11851407
Abstract
Amide hydrogen exchange has been used to examine the structural dynamics and energetics of the interaction of a peptide corresponding to the calmodulin-binding domain of smooth muscle myosin light chain kinase (smMLCKp) with calcium-saturated calmodulin. Heteronuclear NMR (15)N-(1)H correlation spectroscopy was used to quantify amide proton exchange rates of the uniformly (15)N-labeled domain bound to calmodulin. A key feature of a proposed model for molecular recognition by calmodulin [Ehrhardt et al. (1995) Biochemistry 34, 2731-2738] is tested by examination of the dependence of amide hydrogen exchange on applied hydrostatic pressure. Hydrogen exchange rates and corresponding protection factors (1/K(op)) for individual amide protons of the bound smMLCKp domain span 5 orders of magnitude at ambient pressure. Individual protection factors decrease significantly in a linear fashion with increasing hydrostatic pressure. A common pressure dependence is revealed by a constant large negative volume change across the residues comprising the core of the bound helical domain. The pattern of protection factors and their response to hydrostatic pressure is consistent with a structural reorganization that results in the concerted disruption of ion pairs between calmodulin and the bound domain. These observations reinforce a model for the molecular recognition pathway where formation of the initial encounter complex is followed by helix-coil transitions in the bound state and subsequent concerted formation of the extensive ion pair network defining the intermolecular contact surface between CaM and the target domain in the final, compact complex structure.
Details
- Title: Subtitle
- Dissection of the pathway of molecular recognition by calmodulin
- Creators
- James K Kranz - The Johnson Research Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6059, USAPeter F FlynnErnesto J FuentesA Joshua Wand
- Resource Type
- Journal article
- Publication Details
- Biochemistry (Easton), Vol.41(8), pp.2599-2608
- Publisher
- United States
- DOI
- 10.1021/bi011818f
- PMID
- 11851407
- ISSN
- 0006-2960
- eISSN
- 1520-4995
- Grant note
- GM20206 / NIGMS NIH HHS DK39806 / NIDDK NIH HHS
- Language
- English
- Date published
- 02/26/2002
- Academic Unit
- Biochemistry and Molecular Biology
- Record Identifier
- 9984025276702771
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