Major cold shock proteins, CspA from Escherichia coli and CspB from Bacillus subtilis, interact differently with single-stranded DNA templates.
The family of bacterial major cold shock proteins is characterized by a conserved sequence of 65-75 amino acid residues long which form a three-dimensional structure consisting of five beta-sheets arranged into a beta-barrel topology. CspA from Escherichia coli and CspB from Bacillus subtilis are typical representative members of this class of proteins. The exact biological role of these proteins is still unclear; however, they have been implicated to possess ssDNA-binding activity. In this paper, we report the results of a comparative quantitative analysis of ssDNA-binding activity of CspA and CspB. We show that in spite of high homology on the level of primary structure and very similar three-dimensional structures, CspA and CspB have different ssDNA-binding properties. Both proteins preferentially bind polypyrimidine ssDNA templates, but CspB binds to the T-based templates with one order of magnitude higher affinity than to U- or C-based ssDNA, whereas CspA binds T-, U- or C-based ssDNA with comparable affinity. They also show similarities and differences in their binding to ssDNA at high ionic strength. The results of these findings are related to the chemical structure of DNA bases.
Lopez
M M
MM
Department of Biochemistry and Molecular Biology/H171, Penn State University College of Medicine, Hershey, PA 17033, USA.
Makhatadze
G I
GI
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D017931:DNA Primers; D004277:DNA, Single-Stranded / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D008969:Molecular Sequence Data; D016601:RNA-Binding Proteins; D017386:Sequence Homology, Amino Acid; D013050:Spectrometry, Fluorescence; D013698:Templates, Genetic
D001426:Bacterial Proteins; D002352:Carrier Proteins; C491179:CspB protein, E coli; D017931:DNA Primers; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D016601:RNA-Binding Proteins; C062260:cold shock protein CS7.4, Bacteria; C077188:cold-shock protein CspB, Bacteria