PURA

Pur-alpha is a protein that in humans is encoded by the PURA gene located at chromosome 5, band q31. Pur-alpha is an ancient, multi-functional DNA- and RNA-binding protein. PURA is expressed in every human tissue, where it exists as a protein of 322 amino acids. According to convention, PURA, the gene, is written italicized in all upper case letters. Pur-alpha, the protein, is written with the first letter capitalized and can be found listed as Pur-alpha, Pur-α, Pura, Puralpha, Pur alpha and Pur1. Evolutionary conservation and function Pur-alpha was the first sequence-specific single-stranded DNA-binding protein to be discovered in higher organisms (GenBank M96684.1; GI:190749). It binds to both single-stranded and double-stranded DNA, making contact with G residues in the purine-rich strand of its binding site. Cumulative data shows that Pur-alpha preferentially binds to the sequence (G2-4N1-3)n, where N is not G. N denotes a nucleotide, and n denotes the number of repeats of this small sequence. N may be repeated up to three times in this sequence. Following the identification of a Pur factor, which specifically bound a purine-rich sequence in the control region of the c-MYC gene, the gene, PURA, encoding the protein, Pur-alpha, was cloned and sequenced for both human and mouse (GenBank U02098.1). Pur-alpha belongs to the four-member Pur protein family, which also includes Pur-beta (GenBank AY039216.1; GI:14906267) and two forms of Pur–gamma (Variant A, GenBank AF195513.2; Variant B, GenBank AY077841).