<p>Temperature downshift produces a number of changes in cellular physiology including decreased membrane fluidity, reduced mRNA transcription and translation due to the stabilisation of secondary structures, inefficient folding of some proteins, and reduced enzyme activity [<cite idref="PUB00033244"/>]. In response to this, bacteria produce a set of proteins, known as the cold-shock proteins (CSPs), to counteract these harmful effects.</p><p>This entry represents a family of small CSPs consisting of CspA, one of the first cold-shock proteins identified, and its homologues. Note that while some members of this family are induced during cold-shock, some are either constitutively expressed or induced by other stresses such as nutrient starvation. While information about the physiological functions of the CSPs is limited, their structural properties have been well studied [<cite idref="PUB00032978"/>, <cite idref="PUB00029131"/>, <cite idref="PUB00023876"/>, <cite idref="PUB00025145"/>]. These proteins have a five-stranded beta-barrel structural fold and are part of the wider oligonucleotide/oligosaccharide-binding (OB family). They preferentially bind pyrimidine-rich regions of single-stranded RNA and DNA with high affinity, but not double-stranded RNA or DNA. Thus it is postulated that CSPs may act as RNA chaperones by destabilising RNA secondary structures. Experimental evidence suggests that they bind mRNA and regulate ribosomal translation, rate of mRNA dergadation and termination of transcription; functions that are important during normal growth as well as cold shock.</p> Cold shock, CspA