1g9t

<table><tr><td colspan='2'>[[1g9t]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_coli"_migula_1895 "bacillus coli" migula 1895]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1G9T OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=1G9T FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=5GP:GUANOSINE-5-MONOPHOSPHATE'>5GP</scene>, <scene name='pdbligand=N:ANY+5-MONOPHOSPHATE+NUCLEOTIDE'>N</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1a97|1a97]], [[1g9s|1g9s]]</td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">HPT ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 "Bacillus coli" Migula 1895])</td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Hypoxanthine_phosphoribosyltransferase Hypoxanthine phosphoribosyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.2.8 2.4.2.8] </span></td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=1g9t FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1g9t OCA], [http://pdbe.org/1g9t PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1g9t RCSB], [http://www.ebi.ac.uk/pdbsum/1g9t PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1g9t ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/HPRT_ECOLI HPRT_ECOLI]] Acts preferentially on hypoxanthine; has very low activity towards guanine. Inactive towards xanthine.

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== Publication Abstract from PubMed ==

Crystal structures have been determined for free Escherichia coli hypoxanthine phosphoribosyltransferase (HPRT) (2.9 A resolution) and for the enzyme in complex with the reaction products, inosine 5'-monophosphate (IMP) and guanosine 5'-monophosphate (GMP) (2.8 A resolution). Of the known 6-oxopurine phosphoribosyltransferase (PRTase) structures, E. coli HPRT is most similar in structure to that of Tritrichomonas foetus HGXPRT, with a rmsd for 150 Calpha atoms of 1.0 A. Comparison of the free and product bound structures shows that the side chain of Phe156 and the polypeptide backbone in this vicinity move to bind IMP or GMP. A nonproline cis peptide bond, also found in some other 6-oxopurine PRTases, is observed between Leu46 and Arg47 in both the free and complexed structures. For catalysis to occur, the 6-oxopurine PRTases have a requirement for divalent metal ion, usually Mg(2+) in vivo. In the free structure, a Mg(2+) is coordinated to the side chains of Glu103 and Asp104. This interaction may be important for stabilization of the enzyme before catalysis. E. coli HPRT is unique among the known 6-oxopurine PRTases in that it exhibits a marked preference for hypoxanthine as substrate over both xanthine and guanine. The structures suggest that its substrate specificity is due to the modes of binding of the bases. In E. coli HPRT, the carbonyl oxygen of Asp163 would likely form a hydrogen bond with the 2-exocyclic nitrogen of guanine (in the HPRT-guanine-PRib-PP-Mg(2+) complex). However, hypoxanthine does not have a 2-exocyclic atom and the HPRT-IMP structure suggests that hypoxanthine is likely to occupy a different position in the purine-binding pocket.

Crystal structures of free, IMP-, and GMP-bound Escherichia coli hypoxanthine phosphoribosyltransferase.,Guddat LW, Vos S, Martin JL, Keough DT, de Jersey J Protein Sci. 2002 Jul;11(7):1626-38. PMID:12070315<ref>PMID:12070315</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

<references/>

[[Category: Bacillus coli migula 1895]]

[[Category: Hypoxanthine phosphoribosyltransferase]]

[[Category: Guddat, L W]]

[[Category: Jersey, J de]]

[[Category: Martin, J L]]

[[Category: Vos, S]]

[[Category: Keough, D T]]

[[Category: Enzymology]]

[[Category: Transferase]]