1r0s
From Proteopedia
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Crystal structure of ADP-ribosyl cyclase Glu179Ala mutant
Overview
ADP-ribosyl cyclase catalyzes the elimination of nicotinamide from NAD and, cyclization to cADPR, a known second messenger in cellular calcium, signaling pathways. We have determined to 2.0 A resolution the structure, of Aplysia cyclase with ribose-5-phosphate bound covalently at C3' and, with the base exchange substrate (BES), pyridylcarbinol, bound to the, active site. In addition, further refinement at 2.4 A resolution of the, structure of nicotinamide-bound cyclase, which was previously reported, reveals that ribose-5-phosphate is also covalently bound in this, structure, and a second nicotinamide site was identified. The structures, of native and mutant Glu179Ala cyclase were also solved to 1.7 and 2.0 A, respectively. It is proposed that the second nicotinamide site serves to, promote cyclization by clearing the active site of the nicotinamide, byproduct. Moreover, a ribosylation mechanism can be proposed in which the, cyclization reaction proceeds through a covalently bound intermediate.
About this Structure
1R0S is a Single protein structure of sequence from Aplysia californica. Active as NAD(+) nucleosidase, with EC number 3.2.2.5 Full crystallographic information is available from OCA.
Reference
ADP-ribosyl cyclase; crystal structures reveal a covalent intermediate., Love ML, Szebenyi DM, Kriksunov IA, Thiel DJ, Munshi C, Graeff R, Lee HC, Hao Q, Structure. 2004 Mar;12(3):477-86. PMID:15016363
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