Stability and folding properties of a model beta-sheet protein, Escherichia coli CspA.


Abstract

Although beta-sheets represent a sizable fraction of the secondary structure found in proteins, the forces guiding the formation of beta-sheets are still not well understood. Here we examine the folding of a small, all beta-sheet protein, the E. coli major cold shock protein CspA, using both equilibrium and kinetic methods. The equilibrium denaturation of CspA is reversible and displays a single transition between folded and unfolded states. The kinetic traces of the unfolding and refolding of CspA studied by stopped-flow fluorescence spectroscopy are monoexponential and thus also consistent with a two-state model. In the absence of denaturant, CspA refolds very fast with a time constant of 5 ms. The unfolding of CspA is also rapid, and at urea concentrations above the denaturation midpoint, the rate of unfolding is largely independent of urea concentration. This suggests that the transition state ensemble more closely resembles the native state in terms of solvent accessibility than the denatured state. Based on the model of a compact transition state and on an unusual structural feature of CspA, a solvent-exposed cluster of aromatic side chains, we propose a novel folding mechanism for CspA. We have also investigated the possible complications that may arise from attaching polyhistidine affinity tags to the carboxy and amino termini of CspA. Study holds ProTherm entries: 9374, 9375, 9376, 9377, 9378, 9379, 9380, 9381, 9382, 9383, 9384, 9385, 9386, 9387, 9388, 9389, 9390, 9391 Extra Details: cold shock; fast protein folding; polyhistidine tags; protein stability; stopped-flow

Submission Details

ID: mr4QMkza3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:37 p.m.

Version: 1

Publication Details
Reid KL;Rodriguez HM;Hillier BJ;Gregoret LM,Protein Sci. (1998) Stability and folding properties of a model beta-sheet protein, Escherichia coli CspA. PMID:9521124
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P
 

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)


Relevant PDB Entries

Structure ID Release Date Resolution Structure Title
2L15 2010-09-15 Solution Structure of Cold Shock Protein CspA Using Combined NMR and CS-Rosetta method
3MEF 1998-10-14 MAJOR COLD-SHOCK PROTEIN FROM ESCHERICHIA COLI SOLUTION NMR STRUCTURE
2BH8 2005-02-07 1.9 Combinatorial Protein 1b11
1MJC 1994-06-22 2.0 CRYSTAL STRUCTURE OF CSPA, THE MAJOR COLD SHOCK PROTEIN OF ESCHERICHIA COLI

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Cold shock protein CspA Q53816 CSPA_SHIBO
100.0 Cold shock protein CspA Q56178 CSPA_SALVI
100.0 Cold shock protein CspA Q46051 CSPA_CITFR
100.0 Cold shock protein CspA P0A9Y4 CSPA_SHIFL
100.0 Cold shock protein CspA P0A9Y2 CSPA_SALTY
100.0 Cold shock protein CspA P0A9Y3 CSPA_SALTI
100.0 Cold shock protein CspA P0A9Y5 CSPA_SALEN
100.0 Cold shock protein CspA Q46664 CSPA_KLEAK
100.0 Cold shock protein CspA P0A9X9 CSPA_ECOLI
100.0 Cold shock protein CspA P0A9Y0 CSPA_ECOL6
100.0 Cold shock protein CspA P0A9Y1 CSPA_ECO57