1l9x
Structure of gamma-Glutamyl Hydrolase
Structural highlights
FunctionGGH_HUMAN Hydrolyzes the polyglutamate sidechains of pteroylpolyglutamates. Progressively removes gamma-glutamyl residues from pteroylpoly-gamma-glutamate to yield pteroyl-alpha-glutamate (folic acid) and free glutamate. May play an important role in the bioavailability of dietary pteroylpolyglutamates and in the metabolism of pteroylpolyglutamates and antifolates. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedgamma-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. 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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