1m7y
From Proteopedia
Crystal structure of apple ACC synthase in complex with L-aminoethoxyvinylglycine
Overview
The 1.6-A crystal structure of the covalent ketimine complex of apple 1-aminocyclopropane-1-carboxylate (ACC) synthase with the potent inhibitor l-aminoethoxyvinylglycine (AVG) is described. ACC synthase catalyzes the committed step in the biosynthesis of ethylene, a plant hormone that is responsible for the initiation of fruit ripening and for regulating many other developmental processes. AVG is widely used in plant physiology studies to inhibit the activity of ACC synthase. The structural assignment is supported by the fact that the complex absorbs maximally at 341 nm. These results are not in accord with the recently reported crystal structure of the tomato ACC synthase AVG complex, which claims that the inhibitor only associates noncovalently. The rate constant for the association of AVG with apple ACC synthase was determined by stopped-flow spectrophotometry (2.1 x 10(5) m(-1) s(-1)) and by the rate of loss of enzyme activity (1.1 x 10(5) m(-1) s(-1)). The dissociation rate constant determined by activity recovery is 2.4 x 10(-6) s(-1). Thus, the calculated K(d) value is 10-20 pm.
About this Structure
1M7Y is a Single protein structure of sequence from Malus x domestica. Full crystallographic information is available from OCA.
Reference
Apple 1-aminocyclopropane-1-carboxylate synthase in complex with the inhibitor L-aminoethoxyvinylglycine. Evidence for a ketimine intermediate., Capitani G, McCarthy DL, Gut H, Grutter MG, Kirsch JF, J Biol Chem. 2002 Dec 20;277(51):49735-42. Epub 2002 Sep 11. PMID:12228256 Page seeded by OCA on Sat May 3 00:44:53 2008
