1iax: Difference between revisions

[[Image:1iax.jpg|left|200px]]<br /><applet load="1iax" size="350" color="white" frame="true" align="right" spinBox="true"  

The structures of tomato 1-aminocyclopropane-1-carboxylate synthase (ACS) in complex with either cofactor pyridoxal-5'-phosphate (PLP) or both PLP and inhibitor aminoethoxyvinylglycine have been determined by x-ray crystallography. The structures showed good conservation of the catalytic residues, suggesting a similar catalytic mechanism for ACS and other PLP-dependent enzymes. However, the proximity of Tyr152 to the C-gamma-S bond of model substrate S-adenosylmethionine implies its critical role in the catalysis. The concerted accomplishment of catalysis by cofactor PLP and a protein residue, as proposed on the basis of the ACS structures in this paper, may represent a general scheme for the diversity of PLP-dependent catalyses. PLP-dependent enzymes have been categorized into four types of folds. A structural comparison revealed that a core fragment of ACS in fold type I is superimposable over tryptophan synthase beta subunit in fold type II and mouse ornithine decarboxylase in fold type III, thus suggesting a divergent evolution of PLP-dependent enzymes.

1IAX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Solanum_lycopersicum Solanum lycopersicum] with <scene name='pdbligand=SO4:'>SO4</scene> and <scene name='pdbligand=PLP:'>PLP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/1-aminocyclopropane-1-carboxylate_synthase 1-aminocyclopropane-1-carboxylate synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.4.1.14 4.4.1.14] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1IAX OCA].  

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