1h63
From Proteopedia
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'''STRUCTURE OF THE REDUCED PENTAERYTHRITOL TETRANITRATE REDUCTASE''' | '''STRUCTURE OF THE REDUCED PENTAERYTHRITOL TETRANITRATE REDUCTASE''' | ||
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[[Category: Barna, T.]] | [[Category: Barna, T.]] | ||
[[Category: Moody, P.]] | [[Category: Moody, P.]] | ||
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Revision as of 15:28, 2 May 2008
STRUCTURE OF THE REDUCED PENTAERYTHRITOL TETRANITRATE REDUCTASE
Overview
Pentaerythritol tetranitrate reductase (PETN reductase) degrades high explosive molecules including nitrate esters, nitroaromatics and cyclic triazine compounds. The enzyme also binds a variety of cyclic enones, including steroids; some steroids act as substrates whilst others are inhibitors. Understanding the basis of reactivity with cyclic enones requires structural information for the enzyme and key complexes formed with steroid substrates and inhibitors. The crystal structure of oxidised and reduced PETN reductase at 1.5 A resolution establishes a close structural similarity to the beta/alpha-barrel flavoenzyme, old yellow enzyme. In complexes of oxidised PETN reductase with progesterone (an inhibitor), 1,4-androstadiene-3,17-dione and prednisone (both substrates) the steroids are stacked over the si-face of the flavin in an orientation different from that reported for old yellow enzyme. The specifically reducible 1,2 unsaturated bonds in 1,4-androstadiene-3,17-dione and prednisone are not optimally aligned with the flavin N5 in oxidised enzyme complexes. These structures suggest either relative "flipping" or shifting of the steroid with respect to the flavin when bound in different redox forms of the enzyme. Deuterium transfer from nicotinamide coenzyme to 1,4-androstadiene-3,17-dione via the enzyme bound FMN indicates 1alpha addition at the steroid C2 atom. These studies rule out lateral motion of the steroid and indicate that the steroid orientation is "flipped" in different redox states of the enzyme.
About this Structure
1H63 is a Single protein structure of sequence from Enterobacter cloacae. Full crystallographic information is available from OCA.
Reference
Crystal structure of pentaerythritol tetranitrate reductase: "flipped" binding geometries for steroid substrates in different redox states of the enzyme., Barna TM, Khan H, Bruce NC, Barsukov I, Scrutton NS, Moody PC, J Mol Biol. 2001 Jul 6;310(2):433-47. PMID:11428899 Page seeded by OCA on Fri May 2 18:28:55 2008