1GTQ

6-PYRUVOYL TETRAHYDROPTERIN SYNTHASE

Summary for 1GTQ

• Entry DOI: 10.2210/pdb1gtq/pdb
• Descriptor: 6-PYRUVOYL TETRAHYDROPTERIN SYNTHASE, ZINC ION (3 entities in total)
• Functional Keywords: phosphate elimination, pterine synthesis, tetrahydrobiopterin biosynthesis
• Biological source: Rattus rattus (black rat)
• Total number of polymer chains: 2
• Total formula weight: 31881.15

Authors

Nar, H.,Huber, R.,Heizmann, C.W.,Thoeny, B.,Buergisser, D. (deposition date: 1995-09-16, release date: 1996-04-03, Last modification date: 2024-02-07)

Primary citation

Nar, H.,Huber, R.,Heizmann, C.W.,Thony, B.,Burgisser, D.
Three-dimensional structure of 6-pyruvoyl tetrahydropterin synthase, an enzyme involved in tetrahydrobiopterin biosynthesis.
EMBO J., 13:1255-1262, 1994

PubMed Abstract: 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.

PubMed: 8137809

Experimental method

X-RAY DIFFRACTION (2.3 Å)