Single-stranded DNA bound to bacterial cold-shock proteins:: preliminary crystallographic and Raman analysis

The cold-shock response has been described for several bacterial species. It is characterized by distinct changes in intracellular protein patterns whereby a set of cold-shock-inducible proteins become abundant. The major cold-shock proteins of Bacillus subtilis (Bs-CspB) and Bacillus caldolyticus (Bc-Csp) are small oligonucleotide/ oligosaccharide-binding (OB) fold proteins that have been described as binding single-stranded nucleic acids. Bs-CspB (M-r=7365) and Bc-Csp (M-r=7333) were crystallized in the presence of the deoxyhexanucleotide (dT)(6). Crystals of (dT)(6) with Bs-CspB grew in the orthorhombic space group C222(1), with unit-cell parameters a=49.0, b=53.2, c=77.0 Angstrom. Crystals with Bc-Csp grew in the primitive orthorhombic space group P2(1)2(1)2, with unit-cell parameters a=74.3, b=64.9, c=31.2 Angstrom. These crystals diffract to maximal resolutions of 1.78 and 1.29 Angstrom, respectively. The presence of protein and DNA in the crystals was demonstrated by Raman spectroscopy.