Crystal structure of CspA, the major cold shock protein of Escherichia coli.

Abstract

The major cold shock protein of Eschenchia coli, CspA, produced upon a rapid downshift in growth temperature, Is involved in the transcriptional regulation of at least two genes. The protein shares high homology with the nucleic acid-binding do of the Y-box factors, a family of eukaryotic proteins involved in nscriptional and trandational regulation. The crystal structure of CspA has been determined at 2-A resolution and refined to R = 0.187. CspA Is composed of five antiparallel -strands forming a osed five-stranded (-barrel. The three-dimensional structure of CspA Is similar to that of the major cold shock protein of BaciUlus subtils, CspB, which has recently been determined at 2.45-A resolution. However, in contrast to CspB, no dimer Is formed in the crystal. The surface of CspA is characteristic for a protein interacting with single-stranded nucleic acds. Due to the high homology of the bacterial cold shock proteins with the Y-box factors, E. coft CspA and B. subdis CspB define a sructural framework for the common cold shock domain.The cold shock response inEscherichia colifollows an abrupt shift in growth temperature from 370C to 100C, inducing a lag phase in cell growth of 4-5 hr. It is accompanied by a severe reduction in protein synthesis (1). As a consequence of this cold shock, the relative rate of production of at least 14 cold shock proteins is increased. For 13 out of the 14 proteins the increase is 2-to 10-fold whereas synthesis of the major cold shock protein, CspA (CS 7.4), increases at least 100-fold, reaching a level of >10% oftotal protein synthesis at 100C (2). Other proteins expressed as part of the cold shock response of E. coli include NusA, RecA, polynucleotide phosphorylase, translation initiation factors 2a and 2p, pyruvate dehydrogenase (lipoamide), dihydrolipoamide acetyltransferase of pyruvate dehydrogenase, the nucleoid protein H-NS, and subunit A of DNA gyrase (1,3,4).CspA is a small hydrophilic protein consisting of 70 amino acids. It has striking similarity, at the level of 43% sequence identity (Fig. 1), with one domain ofthe Y-box factors, which is referred to as the cold shock domain (5, 6). The Y-box factors are a family of eukaryotic nucleic acid-binding proteins that preferentially bind to the Y box, an element of sequence CTAAIT-ClQYYAA found in the promoter regions of mammalian major histocompatibility complex class II genes (6). Within this sequence the underlined pentamer is especially conserved. Members of this family have also been found to bind to mRNA and to regulate translation in germ cells (7,8).CspA was shown to act as a transcriptional activator of the hns and gyrA genes encoding two other cold shock proteins (3,4). The promoter of hns contains one ATTGG element, whereas the promoter of gyrA contains three such elements, one of which is required for specific CspA-DNA interaction (4). ATTGG elements have been identified also in the promoter regions of genes encoding RecA, NusA, and polynucleotide phosphorylase, suggesting a common mechanism for induction...

In vivo involvement of mutated initiation factor IF1 in gene expression control at the translational level

“…IF1 displays a striking structural resemblance to the major cold shock protein CspA [34,35]. It has also been shown that heterologous expression of IF1 from E. coli in a Bacillus subtilis cspB/cspC double deletion strain complemented the loss of the cold shock induced protein CspB in B. subtilis (the homolog of CspA in E. coli) [36].…”

Differential thermoregulation of two highly homologous cold‐shock genes, cspA and cspB, of Escherichia coli

“…A similar sequence motif (coldshock domain) has been found in eukaryotic DNA and RNA binding proteins called Y-box proteins (Wolffe et al 1992). The three-dimensional structure of CspA has been determined by NMR spectroscopy (Newkirk et al 1994) as well as X-ray crystallography (Schindelin et al 1994). It consists of five antiparallel -sheet structures, and seven surface aromatic residues were shown to interact with single-stranded DNA.…”

Conservation of the Cold Shock Domain Protein Family in Plants

“…CspA, the most prominent of the nine-member E. coli CSP family, accumulates up to 10% of total proteins during cold stress (Jiang et al, 1997). The three-dimensional structure of E. coli CspA forms a five-stranded ␤-barrel structure (Newkirk et al, 1994;Schindelin et al, 1994) that contains two consensus RNA-binding motifs (RNP1 and RNP2), which facilitate nucleic acid recognition/binding (Schroder et al, 1995). CspA has been hypothesized to prevent RNA secondary structure formation (Jiang et al, 1997), thereby enhancing translation at low temperature.…”