1gtq
From Proteopedia
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[[Image:1gtq.gif|left|200px]] | [[Image:1gtq.gif|left|200px]] | ||
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'''6-PYRUVOYL TETRAHYDROPTERIN SYNTHASE''' | '''6-PYRUVOYL TETRAHYDROPTERIN SYNTHASE''' | ||
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[[Category: Nar, H.]] | [[Category: Nar, H.]] | ||
[[Category: Thoeny, B.]] | [[Category: Thoeny, B.]] | ||
| - | [[Category: | + | [[Category: Phosphate elimination]] |
| - | [[Category: | + | [[Category: Pterine synthesis]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 17:59:47 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 14:59, 2 May 2008
6-PYRUVOYL TETRAHYDROPTERIN SYNTHASE
Overview
The crystal structure of rat liver 6-pyruvoyl tetrahydropterin synthase has been solved by multiple isomorphous replacement and refined to a crystallographic R-factor of 20.4% at 2.3 A resolution. 6-Pyruvoyl tetrahydrobiopterin synthase catalyses the conversion of dihydroneopterin triphosphate to 6-pyruvoyl tetrahydropterin, the second of three enzymatic steps in the synthesis of tetrahydrobiopterin from GTP. The functional enzyme is a hexamer of identical subunits. The 6-pyruvoyl tetrahydropterin synthase monomer folds into a sequential, four-stranded, antiparallel beta-sheet with a 25 residue, helix-containing insertion between strands 1 and 2 at the bottom of the molecule, and a segment between strands 2 and 3 forming a pair of antiparallel helices, layered on one side of the beta-sheet. Three 6-pyruvoyl tetrahydropterin synthase monomers form an unusual 12-stranded antiparallel beta-barrel by tight association between the N- and C-terminal beta-strands of two adjacent subunits. The barrel encloses a highly basic pore of 6-12 A diameter. Two trimers associate in a head-to-head fashion to form the active enzyme complex. The substrate-binding site is located close to the trimer-trimer interface and comprises residues from three monomers: A, A' and B. A metal-binding site in the substrate-binding pocket is formed by the three histidine residues 23, 48 and 50 from one 6-pyruvoyl tetrahydropterin synthase subunit. Close to the metal, but apparently not liganding it, are residues Cys42, Glu133 (both from A) and His89 (from B), which might serve as proton donors and acceptors during catalysis.
About this Structure
1GTQ is a Single protein structure of sequence from Rattus rattus. Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of 6-pyruvoyl tetrahydropterin synthase, an enzyme involved in tetrahydrobiopterin biosynthesis., Nar H, Huber R, Heizmann CW, Thony B, Burgisser D, EMBO J. 1994 Mar 15;13(6):1255-62. PMID:8137809 Page seeded by OCA on Fri May 2 17:59:47 2008
