Poly(A) Polymerase

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Revision as of 11:42, 21 November 2007

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spinqualitylabelsall models 2q66, resolution 1.800Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Structure of Yeast Poly(A) Polymerase with ATP and oligo(A)

Overview

We report the 1.8 A structure of yeast poly(A) polymerase (PAP) trapped in, complex with ATP and a five residue poly(A) by mutation of the, catalytically required aspartic acid 154 to alanine. The enzyme has, undergone significant domain movement and reveals a closed conformation, with extensive interactions between the substrates and all three, polymerase domains. Both substrates and 31 buried water molecules are, enclosed within a central cavity that is open at both ends. Four PAP, mutants were subjected to detailed kinetic analysis, and studies of the, adenylyltransfer (forward), pyrophosphorolysis (reverse), and, nucleotidyltransfer reaction utilizing CTP for the mutants are presented., The results support a model in which binding of both poly(A) and the, correct nucleotide, MgATP, induces a conformational change, resulting in, formation of a stable, closed enzyme state. Thermodynamic considerations, of the data are discussed as they pertain to domain closure, substrate, specificity, and catalytic strategies utilized by PAP.

About this Structure

2Q66 is a Single protein structure of sequence from Saccharomyces cerevisiae with MG, ATP and EDO as ligands. Active as Polynucleotide adenylyltransferase, with EC number 2.7.7.19 Full crystallographic information is available from OCA.

Reference

Mechanism of poly(A) polymerase: structure of the enzyme-MgATP-RNA ternary complex and kinetic analysis., Balbo PB, Bohm A, Structure. 2007 Sep;15(9):1117-31. PMID:17850751

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