1ueh

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spinqualitylabelsall models 1ueh, resolution 1.73Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

E. coli undecaprenyl pyrophosphate synthase in complex with Triton X-100, magnesium and sulfate

Overview

Undecaprenyl pyrophosphate synthase (UPPs) catalyzes chain elongation of, farnesyl pyrophosphate (FPP) to undecaprenyl pyrophosphate (UPP) via, condensation with eight isopentenyl pyrophosphates (IPP). UPPs from, Escherichia coli is a dimer, and each subunit consists of 253 amino acid, residues. The chain length of the product is modulated by a hydrophobic, active site tunnel. In this paper, the crystal structure of E. coli UPPs, was refined to 1.73 A resolution, which showed bound sulfate and magnesium, ions as well as Triton X-100 molecules. The amino acid residues 72-82, which encompass an essential catalytic loop not seen in the previous, apoenzyme structure (Ko, T.-P., Chen, Y. K., Robinson, H., Tsai, P. C., Gao, Y.-G., Chen, A. P.-C., Wang, A. H.-J., and Liang, P.-H. (2001) J., Biol. Chem. 276, 47474-47482), also became visible in one subunit. The, sulfate ions suggest locations of the pyrophosphate groups of FPP and IPP, in the active site. The Mg2+ is chelated by His-199 and Glu-213 from, different subunits and possibly plays a structural rather than catalytic, role. However, the metal ion is near the IPP-binding site, and double, mutation of His-199 and Glu-213 to alanines showed a remarkable increase, of Km value for IPP. Inside the tunnel, one Triton surrounds the top, portion of the tunnel, and the other occupies the bottom part. These two, Triton molecules may mimic the hydrocarbon moiety of the UPP product in, the active site. Kinetic analysis indicated that a high concentration, (>1%) of Triton inhibits the enzyme activity.

About this Structure

1UEH is a Single protein structure of sequence from Escherichia coli with SO4, MG, OXN and UNK as ligands. Active as Di-trans,poly-cis-decaprenylcistransferase, with EC number 2.5.1.31 Full crystallographic information is available from OCA.

Reference

Catalytic mechanism revealed by the crystal structure of undecaprenyl pyrophosphate synthase in complex with sulfate, magnesium, and triton., Chang SY, Ko TP, Liang PH, Wang AH, J Biol Chem. 2003 Aug 1;278(31):29298-307. Epub 2003 May 19. PMID:12756244

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