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Crystal Structure of Human Soluble Adenylate Cyclase Reveals a Distinct, Highly Flexible Allosteric Bicarbonate Binding Pocket
Author(s) -
SaalauBethell Susanne M.,
Berdini Valerio,
Cleasby Anne,
Congreve Miles,
Coyle Joseph E.,
Lock Victoria,
Murray Christopher W.,
O'Brien M. Alistair,
Rich Sharna J.,
Sambrook Tracey,
Vinkovic Mladen,
Yon Jeff R.,
Jhoti Harren
Publication year - 2014
Publication title -
chemmedchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.817
H-Index - 100
eISSN - 1860-7187
pISSN - 1860-7179
DOI - 10.1002/cmdc.201300480
Subject(s) - allosteric regulation , adenylate kinase , active site , cyclase , binding site , chemistry , activator (genetics) , enzyme , bicarbonate , adenosine monophosphate , allosteric enzyme , plasma protein binding , adenosine triphosphate , biochemistry , stereochemistry , receptor , organic chemistry
Soluble adenylate cyclases catalyse the synthesis of the second messenger cAMP through the cyclisation of ATP and are the only known enzymes to be directly activated by bicarbonate. Here, we report the first crystal structure of the human enzyme that reveals a pseudosymmetrical arrangement of two catalytic domains to produce a single competent active site and a novel discrete bicarbonate binding pocket. Crystal structures of the apo protein, the protein in complex with α,β‐methylene adenosine 5′‐triphosphate (AMPCPP) and calcium, with the allosteric activator bicarbonate, and also with a number of inhibitors identified using fragment screening, all show a flexible active site that undergoes significant conformational changes on binding of ligands. The resulting nanomolar‐potent inhibitors that were developed bind at both the substrate binding pocket and the allosteric site, and can be used as chemical probes to further elucidate the function of this protein.