1f5a
From Proteopedia
CRYSTAL STRUCTURE OF MAMMALIAN POLY(A) POLYMERASE
Overview
In eukaryotes, polyadenylation of pre-mRNA plays an essential role in the initiation step of protein synthesis, as well as in the export and stability of mRNAs. Poly(A) polymerase, the enzyme at the heart of the polyadenylation machinery, is a template-independent RNA polymerase which specifically incorporates ATP at the 3' end of mRNA. We have solved the crystal structure of bovine poly(A) polymerase bound to an ATP analog at 2.5 A resolution. The structure revealed expected and unexpected similarities to other proteins. As expected, the catalytic domain of poly(A) polymerase shares substantial structural homology with other nucleotidyl transferases such as DNA polymerase beta and kanamycin transferase. The C-terminal domain unexpectedly folds into a compact domain reminiscent of the RNA-recognition motif fold. The three invariant aspartates of the catalytic triad ligate two of the three active site metals. One of these metals also contacts the adenine ring. Furthermore, conserved, catalytically important residues contact the nucleotide. These contacts, taken together with metal coordination of the adenine base, provide a structural basis for ATP selection by poly(A) polymerase.
About this Structure
1F5A is a Single protein structure of sequence from Bos taurus. Full crystallographic information is available from OCA.
Reference
Crystal structure of mammalian poly(A) polymerase in complex with an analog of ATP., Martin G, Keller W, Doublie S, EMBO J. 2000 Aug 15;19(16):4193-203. PMID:10944102 Page seeded by OCA on Fri May 2 15:55:10 2008
