2hji
From Proteopedia
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Structural model for the Fe-containing isoform of acireductone dioxygenase
Overview
Acireductone dioxygenase (ARD) catalyzes different reactions between O2, and 1,2-dihydroxy-3-oxo-5-(methylthio)pent-1-ene (acireductone) depending, upon the metal bound in the active site. Ni2+ -ARD cleaves acireductone to, formate, CO and methylthiopropionate. If Fe2+ is bound (ARD'), the same, substrates yield methylthioketobutyrate and formate. The two forms differ, in structure, and are chromatographically separable. Paramagnetism of Fe2+, renders the active site of ARD' inaccessible to standard NMR methods. The, structure of ARD' has been determined using Fe2+ binding parameters, determined by X-ray absorption spectroscopy and NMR restraints from H98S, ARD, a metal-free diamagnetic protein that is isostructural with ARD'., ARD' retains the beta-sandwich fold of ARD, but a structural entropy, switch increases order at one end of a two-helix system that bisects the, beta-sandwich and decreases order at the other upon interconversion of ARD, and ARD', causing loss of the C-terminal helix in ARD' and rearrangements, of residues involved in substrate orientation in the active site.
About this Structure
2HJI is a Single protein structure of sequence from Klebsiella oxytoca with as ligand. Active as Acireductone dioxygenase (Fe(2+)-requiring), with EC number 1.13.11.54 Full crystallographic information is available from OCA.
Reference
One protein, two enzymes revisited: a structural entropy switch interconverts the two isoforms of acireductone dioxygenase., Ju T, Goldsmith RB, Chai SC, Maroney MJ, Pochapsky SS, Pochapsky TC, J Mol Biol. 2006 Nov 3;363(4):823-34. Epub 2006 Aug 26. PMID:16989860
Page seeded by OCA on Tue Jan 29 20:22:29 2008
