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1l9x
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(New page: 200px<br /> <applet load="1l9x" size="450" color="white" frame="true" align="right" spinBox="true" caption="1l9x, resolution 1.6Å" /> '''Structure of gamma-G...)
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Revision as of 15:51, 12 November 2007
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Structure of gamma-Glutamyl Hydrolase
Overview
gamma-Glutamyl hydrolase catalyzes the cleavage of the gamma-glutamyl, chain of folylpoly-gamma-glutamyl substrates and is a central enzyme in, folyl and antifolyl poly-gamma-glutamate metabolism. The crystal structure, of human gamma-glutamyl hydrolase, determined at 1.6-A resolution, reveals, that the protein is a homodimer. The overall structure of human, gamma-glutamyl hydrolase contains 11 alpha-helices and 14 beta-strands, with a fold in which a central eight-stranded beta-sheet is sandwiched by, three and five alpha-helices on each side. The topology is very similar to, that of the class I glutamine amidotransferase domains, with the only, major differences consisting of extensions in four loops and at the C, terminus. These insertions are important for defining the substrate, binding cleft and/or the dimer interface. Two sequence motifs are found in, common between human gamma-glutamyl hydrolase and the class I glutamine, amidotransferase family and include the catalytically essential residues, Cys-110 and His-220. These residues are located in the center of a large, l-shaped cleft that is closed at one end and open at the other. Several, conserved residues, including Glu-114, His-171, Gln-218, and Lys-223, may, be important for substrate binding. Modeling of a methotrexate thioester, intermediate, based on the corresponding complex of the glutamate, thioester intermediate of Escherichia coli carbamoyl-phosphate synthetase, indicates that the substrate binds in an orientation with the pteroyl, group toward the open end of the cleft.
About this Structure
1L9X is a Single protein structure of sequence from Homo sapiens with BME as ligand. Active as Gamma-glutamyl hydrolase, with EC number 3.4.19.9 Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of human gamma -glutamyl hydrolase. A class I glatamine amidotransferase adapted for a complex substate., Li H, Ryan TJ, Chave KJ, Van Roey P, J Biol Chem. 2002 Jul 5;277(27):24522-9. Epub 2002 Apr 12. PMID:11953431
Page seeded by OCA on Mon Nov 12 17:58:09 2007
