1g9t
From Proteopedia
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| - | [[Image:1g9t.jpg|left|200px]] | + | [[Image:1g9t.jpg|left|200px]] |
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| - | '''CRYSTAL STRUCTURE OF E.COLI HPRT-GMP COMPLEX''' | + | {{Structure |
| + | |PDB= 1g9t |SIZE=350|CAPTION= <scene name='initialview01'>1g9t</scene>, resolution 2.8Å | ||
| + | |SITE= | ||
| + | |LIGAND= <scene name='pdbligand=5GP:GUANOSINE-5'-MONOPHOSPHATE'>5GP</scene> and <scene name='pdbligand=N:ANY 5'-MONOPHOSPHATE NUCLEOTIDE'>N</scene> | ||
| + | |ACTIVITY= [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] | ||
| + | |GENE= HPT ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 Escherichia coli]) | ||
| + | }} | ||
| + | |||
| + | '''CRYSTAL STRUCTURE OF E.COLI HPRT-GMP COMPLEX''' | ||
| + | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1G9T is a [ | + | 1G9T is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1G9T OCA]. |
==Reference== | ==Reference== | ||
| - | 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:[http:// | + | 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:[http://www.ncbi.nlm.nih.gov/pubmed/12070315 12070315] |
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Hypoxanthine phosphoribosyltransferase]] | [[Category: Hypoxanthine phosphoribosyltransferase]] | ||
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[[Category: crystal structure]] | [[Category: crystal structure]] | ||
[[Category: enzymology]] | [[Category: enzymology]] | ||
| - | [[Category: | + | [[Category: phosphoribosyltransferase]] |
[[Category: protein chemistry]] | [[Category: protein chemistry]] | ||
[[Category: purine salvage]] | [[Category: purine salvage]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 11:20:14 2008'' |
Revision as of 09:20, 20 March 2008
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| , resolution 2.8Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | and | ||||||
| Gene: | HPT (Escherichia coli) | ||||||
| Activity: | Hypoxanthine phosphoribosyltransferase, with EC number 2.4.2.8 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
CRYSTAL STRUCTURE OF E.COLI HPRT-GMP COMPLEX
Overview
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.
About this Structure
1G9T is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
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
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