1e6a

From Proteopedia

Revision as of 10:34, 30 October 2007

FLUORIDE-INHIBITED SUBSTRATE COMPLEX OF SACCHAROMYCES CEREVISIAE INORGANIC PYROPHOSPHATASE

Overview

The wealth of kinetic and structural information makes inorganic, pyrophosphatases (PPases) a good model system to study the details of, enzymatic phosphoryl transfer. The enzyme accelerates metal-complexed, phosphoryl transfer 10(10)-fold: but how? Our structures of the yeast, PPase product complex at 1.15 A and fluoride-inhibited complex at 1.9 A, visualize the active site in three different states: substrate-bound, immediate product bound, and relaxed product bound. These span the steps, around chemical catalysis and provide strong evidence that a water, molecule (O(nu)) directly attacks PPi with a pK(a) vastly lowered by, coordination to two metal ions and D117. They also suggest that a, low-barrier hydrogen bond (LBHB) forms between D117 and O(nu), in part, because of steric crowding ... [(full description)]

About this Structure

1E6A is a [Single protein] structure of sequence from [Saccharomyces cerevisiae] with MN, F, NA, PO4, POP and POP as [ligands]. Active as [Inorganic diphosphatase], with EC number [3.6.1.1]. Structure known Active Sites: POA and POB. Full crystallographic information is available from [OCA].

Reference

Toward a quantum-mechanical description of metal-assisted phosphoryl transfer in pyrophosphatase., Heikinheimo P, Tuominen V, Ahonen AK, Teplyakov A, Cooperman BS, Baykov AA, Lahti R, Goldman A, Proc Natl Acad Sci U S A. 2001 Mar 13;98(6):3121-6. Epub 2001 Mar 6. PMID:11248042

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