THE CRYSTAL STRUCTURE OF HUMAN HYPOXANTHINE-GUANINE PHOSPHORIBOSYLTRANSFERASE WITH BOUND GMP
[HPRT_HUMAN] Defects in HPRT1 are the cause of Lesch-Nyhan syndrome (LNS) [MIM:300322]. LNS is characterized by complete lack of enzymatic activity that results in hyperuricemia, choreoathetosis, mental retardation, and compulsive self-mutilation.          Defects in HPRT1 are the cause of gout HPRT-related (GOUT-HPRT) [MIM:300323]; also known as HPRT-related gout or Kelley-Seegmiller syndrome. Gout is characterized by partial enzyme activity and hyperuricemia.      [:]
[HPRT_HUMAN] Converts guanine to guanosine monophosphate, and hypoxanthine to inosine monophosphate. Transfers the 5-phosphoribosyl group from 5-phosphoribosylpyrophosphate onto the purine. Plays a central role in the generation of purine nucleotides through the purine salvage pathway.
Publication Abstract from PubMed
The crystal structure of HGPRTase with bound GMP has been determined and refined to 2.5 A resolution. The enzyme has a core alpha/beta structure resembling the nucleotide-binding fold of dehydrogenases, and a second lobe composed of residues from the amino and carboxy termini. The GMP molecule binds in an anti conformation in a solvent-exposed cleft of the enzyme. Lys-165, which forms a hydrogen bond to O6 of GMP, appears to be critical for determining the specificity for guanine and hypoxanthine over adenine. The location of active site residues also provides evidence for a possible mechanism for general base-assisted HGPRTase catalysis. A rationalization of the effects on stability and activity of naturally occurring single amino acid mutations of HGPRTase is presented, including a discussion of several mutations at the active site that lead to Lesch-Nyhan syndrome.
The crystal structure of human hypoxanthine-guanine phosphoribosyltransferase with bound GMP.,Eads JC, Scapin G, Xu Y, Grubmeyer C, Sacchettini JC Cell. 1994 Jul 29;78(2):325-34. PMID:8044844
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.