2gaf
From Proteopedia
Crystal Structure of the Vaccinia Polyadenylate Polymerase Heterodimer (apo form)
Structural highlights
FunctionQ1PIV4_9POXV Displays methyltransferase, positive regulation of the poly(A) polymerase and transcription elongation activities. Involved in the modification of both mRNA ends and in intermediate and late gene positive transcription elongation. At the mRNAs 5' end, methylates the ribose 2' OH group of the first transcribed nucleotide, thereby producing a 2'-O-methylpurine cap. At the 3' end, functions as a processivity factor which stimulates the activity of the viral poly(A) polymerase OPG063 that creates mRNA's poly(A) tail. In the presence of OPG102, OPG063 does not dissociate from the RNA allowing tail elongation to around 250 adenylates.[ARBA:ARBA00034661][PIRNR:PIRNR003726] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedPolyadenylation of mRNAs in poxviruses, crucial for virion maturation, is carried out by a poly(A) polymerase heterodimer composed of a catalytic component, VP55, and a processivity factor, VP39. The ATP-gamma-S bound and unbound crystal structures of the vaccinia polymerase reveal an unusual architecture for VP55 that comprises of N-terminal, central or catalytic, and C-terminal domains with different topologies and that differs from many polymerases, including the eukaryotic poly(A) polymerases. Residues in the active site of VP55, located between the catalytic and C-terminal domains, make specific interactions with the adenine of the ATP analog, establishing the molecular basis of ATP recognition. VP55's concave surface docks the globular VP39. A model for RNA primer binding that involves all three VP55 domains and VP39 is proposed. The model supports biochemical evidence that VP39 functions as a processivity factor by partially enclosing the RNA primer at the heterodimer interface. Crystal structures of the vaccinia virus polyadenylate polymerase heterodimer: insights into ATP selectivity and processivity.,Moure CM, Bowman BR, Gershon PD, Quiocho FA Mol Cell. 2006 May 5;22(3):339-49. PMID:16678106[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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