Surface-exposed phenylalanines in the RNP1/RNP2 motif stabilize the cold-shock protein CspB from Bacillus subtilis.


Abstract

In the cold-shock protein CspB from Bacillus subtilis three exposed Phe residues (F15, F17, and F27) are essential for its function in binding to single-stranded nucleic acids. Usually, the hydrophobic Phe side chains are buried in folded proteins. We asked here whether the exposition of the essential Phe residues could be a cause for the very low conformational stability of CspB. Urea-induced and heat-induced equilibrium unfolding transitions were measured for three mutants of CspB, where Phe 15, Phe 17, and Phe 27 were individually replaced by alanine. Unexpectedly, all three mutations strongly destabilized CspB. The aromatic side chains of Phe 15, Phe 17, and Phe 27 in the active site are thus important for both binding to nucleic acids and conformational stability. There is no compromise between function and stability in the active site. Model calculations indicate that, although they are partially exposed to solvent, all three Phe residues nevertheless lose accessible surface upon folding, and this should favor the native state. A different result is obtained with the F38A variant. Phe 38 is hyperexposed in native CspB, and its substitution by Ala is in fact stabilizing. Study holds ProTherm entries: 3518, 3519, 3520, 3521, 3522, 3523, 3524, 3525, 3526, 3527, 14241, 14242, 14243, 14244 Extra Details: protein stability; cold shock protein; nucleic acid binding;,hydrophobic effect

Submission Details

ID: nCo4xHGR

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:21 p.m.

Version: 1

Publication Details
Schindler T;Perl D;Graumann P;Sieber V;Marahiel MA;Schmid FX,Proteins (1998) Surface-exposed phenylalanines in the RNP1/RNP2 motif stabilize the cold-shock protein CspB from Bacillus subtilis. PMID:9533624
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
1NMF 1996-07-11 MAJOR COLD-SHOCK PROTEIN, NMR, 20 STRUCTURES
1NMG 1996-07-11 MAJOR COLD-SHOCK PROTEIN, NMR, MINIMIZED AVERAGE STRUCTURE
2F52 2006-09-19 Solution structure of cold shock protein CspB from Bacillus subtilis in complex with heptathymidine
3PF4 2011-09-21 1.38 Crystal structure of Bs-CspB in complex with r(GUCUUUA)
3PF5 2011-09-21 1.68 Crystal structure of Bs-CspB in complex with rU6
2ES2 2006-09-05 1.78 Crystal Structure Analysis of the Bacillus Subtilis Cold Shock Protein Bs-CspB in Complex with Hexathymidine
2I5M 2007-05-22 2.3 Crystal structure of Bacillus subtilis cold shock protein CspB variant A46K S48R
1CSP 1995-05-12 2.45 CRYSTAL STRUCTURE OF THE BACILLUS SUBTILIS MAJOR COLD SHOCK PROTEIN, CSPB: A UNIVERSAL NUCLEIC-ACID BINDING DOMAIN
2I5L 2007-05-22 2.55 Crystal structure of Bacillus subtilis Cold Shock Protein variant Bs-CspB M1R/E3K/K65I
1CSQ 1995-05-12 2.7 CRYSTAL STRUCTURE OF THE BACILLUS SUBTILIS MAJOR COLD SHOCK PROTEIN, CSPB: A UNIVERSAL NUCLEIC-ACID BINDING DOMAIN

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
96.5 Cold shock protein CspB P41018 CSPB_SPOGL
92.3 Cold shock protein CspB Q816H3 CSPD_BACCR
92.3 Cold shock protein CspB Q81K90 CSPD_BACAN
100.0 Cold shock protein CspB P32081 CSPB_BACSU