1wc4: Difference between revisions
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==Overview== | ==Overview== | ||
In an evolutionarily conserved signaling pathway, 'soluble' adenylyl, cyclases (sACs) synthesize the ubiquitous second messenger cyclic, adenosine 3',5'-monophosphate (cAMP) in response to bicarbonate and, calcium signals. Here, we present crystal structures of a cyanobacterial, sAC enzyme in complex with ATP analogs, calcium and bicarbonate, which, represent distinct catalytic states of the enzyme. The structures reveal, that calcium occupies the first ion-binding site and directly mediates, nucleotide binding. The single ion-occupied, nucleotide-bound state, defines a novel, open adenylyl cyclase state. In contrast, bicarbonate, increases the catalytic rate by inducing marked active site closure and, recruiting a second, catalytic ion. The phosphates of the bound substrate, analogs are .. | In an evolutionarily conserved signaling pathway, 'soluble' adenylyl, cyclases (sACs) synthesize the ubiquitous second messenger cyclic, adenosine 3',5'-monophosphate (cAMP) in response to bicarbonate and, calcium signals. Here, we present crystal structures of a cyanobacterial, sAC enzyme in complex with ATP analogs, calcium and bicarbonate, which, represent distinct catalytic states of the enzyme. The structures reveal, that calcium occupies the first ion-binding site and directly mediates, nucleotide binding. The single ion-occupied, nucleotide-bound state, defines a novel, open adenylyl cyclase state. In contrast, bicarbonate, increases the catalytic rate by inducing marked active site closure and, recruiting a second, catalytic ion. The phosphates of the bound substrate, analogs are rearranged, which would facilitate product formation and, release. The mechanisms of calcium and bicarbonate sensing define a, reaction pathway involving active site closure and metal recruitment that, may be universal for class III cyclases. | ||
==About this Structure== | ==About this Structure== | ||
1WC4 is a | 1WC4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Arthrospira_platensis Arthrospira platensis] with EU3 and APC as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Adenylate_cyclase Adenylate cyclase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.6.1.1 4.6.1.1] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1WC4 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: soluble adenylyl cyclase]] | [[Category: soluble adenylyl cyclase]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 12:28:09 2007'' | ||
