Poly(A) Polymerase
From Proteopedia
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| , resolution 1.800Å | |||||||
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| Ligands: | , and | ||||||
| Gene: | PAP1 (Saccharomyces cerevisiae) | ||||||
| Activity: | Polynucleotide adenylyltransferase, with EC number 2.7.7.19 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
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. 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
Page seeded by OCA on Thu Mar 20 18:22:12 2008
Proteopedia Page Contributors and Editors (what is this?)
Michal Harel, Eran Hodis, David Canner, Joel L. Sussman, OCA, Alexander Berchansky, Jaime Prilusky, David S. Goodsell, Eric Martz
