1jh7 | pdb_00001jh7
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Semi-reduced Inhibitor-bound Cyclic Nucleotide Phosphodiesterase from Arabidopsis thaliana
Overview
The crystal structure of the semireduced form of cyclic nucleotide, phosphodiesterase (CPDase) from Arabidopsis thaliana has been solved by, molecular replacement and refined at the resolution of 1.8 A. We have, previously reported the crystal structure of the native form of this, enzyme, whose main target is ADP-ribose 1",2"-cyclic phosphate, a product, of the tRNA splicing reaction. CPDase possesses six cysteine residues, four of which are involved in forming two intra-molecular disulfide, bridges. One of these bridges, between Cys-104 and Cys-110, is opened in, the semireduced CPDase, whereas the other remains intact. This change of, the redox state leads to a conformational rearrangement in the loop, covering the active site of the protein. While the native structure shows, this partially disordered loop in a coil conformation, in the semireduced, enzyme the N-terminal lobe of this loop winds up and elongates the, preceding alpha-helix. The semireduced state of CPDase also enabled, co-crystallization with a putative inhibitor of its enzymatic activity, 2',3'-cyclic uridine vanadate. The ligand is bound within the active site, and the mode of binding is in agreement with the previously proposed, enzymatic mechanism. Selected biophysical properties of the oxidized and, the semireduced CPDase are also discussed.
About this Structure
1JH7 is a Single protein structure of sequence from Arabidopsis thaliana with SO4 and UVC as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structures of the semireduced and inhibitor-bound forms of cyclic nucleotide phosphodiesterase from Arabidopsis thaliana., Hofmann A, Grella M, Botos I, Filipowicz W, Wlodawer A, J Biol Chem. 2002 Jan 11;277(2):1419-25. Epub 2001 Nov 1. PMID:11694509
Page seeded by OCA on Tue Nov 20 18:15:12 2007
