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| - | [[Image:1jys.gif|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_1jys| PDB=1jys | SCENE= }} | | {{STRUCTURE_1jys| PDB=1jys | SCENE= }} |
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| - | '''Crystal Structure of E. coli MTA/AdoHcy Nucleosidase'''
| + | ===Crystal Structure of E. coli MTA/AdoHcy Nucleosidase=== |
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| - | ==Overview==
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| - | BACKGROUND: 5'-methylthioadenosine/S-adenosyl-homocysteine (MTA/AdoHcy) nucleosidase catalyzes the irreversible cleavage of 5'-methylthioadenosine and S-adenosylhomocysteine to adenine and the corresponding thioribose, 5'-methylthioribose and S-ribosylhomocysteine, respectively. While this enzyme is crucial for the metabolism of AdoHcy and MTA nucleosides in many prokaryotic and lower eukaryotic organisms, it is absent in mammalian cells. This metabolic difference represents an exploitable target for rational drug design. RESULTS: The crystal structure of E. coli MTA/AdoHcy nucleosidase was determined at 1.90 A resolution with the multiwavelength anomalous diffraction (MAD) technique. Each monomer of the MTA/AdoHcy nucleosidase dimer consists of a mixed alpha/beta domain with a nine-stranded mixed beta sheet, flanked by six alpha helices and a small 3(10) helix. Intersubunit contacts between the two monomers present in the asymmetric unit are mediated primarily by helix-helix and helix-loop hydrophobic interactions. The unexpected presence of an adenine molecule in the active site of the enzyme has allowed the identification of both substrate binding and potential catalytic amino acid residues. CONCLUSIONS: Although the sequence of E. coli MTA/AdoHcy nucleosidase has almost no identity with any known enzyme, its tertiary structure is similar to both the mammalian (trimeric) and prokaryotic (hexameric) purine nucleoside phosphorylases. The structure provides evidence that this protein is functional as a dimer and that the dual specificity for MTA and AdoHcy results from the truncation of a helix. The structure of MTA/AdoHcy nucleosidase is the first structure of a prokaryotic nucleoside N-ribohydrolase specific for 6-aminopurines.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_11591349}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 11591349 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_11591349}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Dimer]] | | [[Category: Dimer]] |
| | [[Category: Mixed alpha/beta]] | | [[Category: Mixed alpha/beta]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 22:05:15 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 21:08:38 2008'' |
Revision as of 18:08, 1 July 2008
Template:STRUCTURE 1jys
Crystal Structure of E. coli MTA/AdoHcy Nucleosidase
Template:ABSTRACT PUBMED 11591349
About this Structure
1JYS is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Structure of E. coli 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase reveals similarity to the purine nucleoside phosphorylases., Lee JE, Cornell KA, Riscoe MK, Howell PL, Structure. 2001 Oct;9(10):941-53. PMID:11591349
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