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- | [[Image:1meo.jpg|left|200px]] | + | {{Seed}} |
| + | [[Image:1meo.png|left|200px]] |
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| {{STRUCTURE_1meo| PDB=1meo | SCENE= }} | | {{STRUCTURE_1meo| PDB=1meo | SCENE= }} |
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- | '''human glycinamide ribonucleotide Transformylase at pH 4.2'''
| + | ===human glycinamide ribonucleotide Transformylase at pH 4.2=== |
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- | ==Overview==
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- | Glycinamide ribonucleotide transformylase (GAR Tfase) is a key folate-dependent enzyme in the de novo purine biosynthesis pathway and, as such, has been the target for antitumor drug design. Here, we describe the crystal structures of the human GAR Tfase (purN) component of the human trifunctional protein (purD-purM-purN) at various pH values and in complex with its substrate. Human GAR Tfase exhibits pH-dependent enzyme activity with its maximum around pH 7.5-8. Comparison of unliganded human GAR Tfase structures at pH 4.2 and pH 8.5 reveals conformational differences in the substrate binding loop, which at pH 4.2 occupies the binding cleft and prohibits substrate binding, while at pH 8.5 is permissive for substrate binding. The crystal structure of GAR Tfase with its natural substrate, beta-glycinamide ribonucleotide (beta-GAR), at pH 8.5 confirms this conformational isomerism. Surprisingly, several important structural differences are found between human GAR Tfase and previously reported E. coli GAR Tfase structures, which have been used as the primary template for drug design studies. While the E. coli structure gave valuable insights into the active site and formyl transfer mechanism, differences in structure and inhibition between the bacterial and mammalian enzymes suggest that the human GAR Tfase structure is now the appropriate template for the design of anti-cancer agents.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_12450384}}, adds the Publication Abstract to the page |
| + | (as it appears on PubMed at http://www.pubmed.gov), where 12450384 is the PubMed ID number. |
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| + | {{ABSTRACT_PUBMED_12450384}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Zhang, Y.]] | | [[Category: Zhang, Y.]] |
| [[Category: Purine biosynthesis]] | | [[Category: Purine biosynthesis]] |
- | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 00:56:59 2008'' | + | |
| + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jul 2 23:48:27 2008'' |
Revision as of 20:48, 2 July 2008
Template:STRUCTURE 1meo
human glycinamide ribonucleotide Transformylase at pH 4.2
Template:ABSTRACT PUBMED 12450384
About this Structure
1MEO is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Crystal structures of human GAR Tfase at low and high pH and with substrate beta-GAR., Zhang Y, Desharnais J, Greasley SE, Beardsley GP, Boger DL, Wilson IA, Biochemistry. 2002 Dec 3;41(48):14206-15. PMID:12450384
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