3mef
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(New page: 200px<br /><applet load="3mef" size="450" color="white" frame="true" align="right" spinBox="true" caption="3mef" /> '''MAJOR COLD-SHOCK PROTEIN FROM ESCHERICHIA CO...)
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Revision as of 17:45, 20 November 2007
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MAJOR COLD-SHOCK PROTEIN FROM ESCHERICHIA COLI SOLUTION NMR STRUCTURE
Overview
The major cold-shock protein (CspA) from Escherichia coli is a, single-stranded nucleic acid-binding protein that is produced in response, to cold stress. We have previously reported its overall chain fold as, determined by NMR spectroscopy [Newkirk, K., Feng, W., Jiang, W., Tejero, R., Emerson, S. D., Inouye, M., and Montelione, G. T. (1994) Proc. Natl., Acad. Sci. U.S.A. 91, 5114-5118]. Here we describe the complete analysis, of 1H, 13C, and 15N resonance assignments for CspA, together with a, refined solution NMR structure based on 699 conformational constraints and, an analysis of backbone dynamics based on 15N relaxation rate, measurements. An extensive set of triple-resonance NMR experiments for, obtaining the backbone and side chain resonance assignments were carried, out on uniformly 13C- and 15N-enriched CspA. Using a subset of these, triple-resonance experiments, the computer program AUTOASSIGN provided, automatic analysis of sequence-specific backbone N, Calpha, C', HN, Halpha, and side chain Cbeta resonance assignments. The remaining 1H, 13C, and 15N resonance assignments for CspA were then obtained by manual, analysis of additional NMR spectra. Dihedral angle constraints and, stereospecific methylene Hbeta resonance assignments were determined using, a new conformational grid search program, HYPER, and used together with, longer-range constraints as input for three-dimensional structure, calculations. The resulting solution NMR structure of CspA is a, well-defined five-stranded beta-barrel with surface-exposed aromatic, groups that form a single-stranded nucleic acid-binding site. Backbone, dynamics of CspA have also been characterized by 15N T1, T2, and, heteronuclear 15N-1H NOE measurements and analyzed using the extended, Lipari-Szabo formalism. These dynamic measurements indicate a molecular, rotational correlation time taum of 4.88 +/- 0.04 ns and provide evidence, for fast time scale (taue < 500 ps) dynamics in surface loops and motions, on the microsecond to millisecond time scale within the proposed nucleic, acid-binding epitope.
About this Structure
3MEF is a Single protein structure of sequence from Escherichia coli. This structure superseeds the now removed PDB entry 1MEF. Full crystallographic information is available from OCA.
Reference
Solution NMR structure and backbone dynamics of the major cold-shock protein (CspA) from Escherichia coli: evidence for conformational dynamics in the single-stranded RNA-binding site., Feng W, Tejero R, Zimmerman DE, Inouye M, Montelione GT, Biochemistry. 1998 Aug 4;37(31):10881-96. PMID:9692981
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