Crystal Structure of Human Soluble Adenylate Cyclase Reveals a Distinct,Highly Flexible Allosteric Bicarbonate Binding Pocket |
| |
| Authors: | Susanne M Saalau‐Bethell Dr Valerio Berdini Dr Anne Cleasby Dr Miles Congreve Dr Joseph E Coyle Victoria Lock Dr Christopher W Murray Dr M Alistair O'Brien Sharna J Rich Tracey Sambrook Dr Mladen Vinkovic Dr Jeff R Yon Dr Harren Jhoti |
| |
| Affiliation: | 1. Astex Pharmaceuticals, Cambridge Science Park, Cambridge, CB4 0QA (UK);2. Heptares Therapeutics Ltd, BioPark, Broadwater Road, Welwyn Garden City, AL7 3AX (UK);3. Gregory Fryer Associates Ltd, 10–12 St Thomas’ Pl, Ely, CB7 4EX (UK);4. StemCell Sciences UK, Babraham Research Campus, Cambridge, CB22 3AT (UK) |
| |
| Abstract: | 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. |
| |
| Keywords: | allosterism drug discovery enzyme regulation fragment screening structural biology |
|
|
