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- | [[Image:1a4m.gif|left|200px]] | + | {{Seed}} |
| + | [[Image:1a4m.png|left|200px]] |
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| {{STRUCTURE_1a4m| PDB=1a4m | SCENE= }} | | {{STRUCTURE_1a4m| PDB=1a4m | SCENE= }} |
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- | '''ADA STRUCTURE COMPLEXED WITH PURINE RIBOSIDE AT PH 7.0'''
| + | ===ADA STRUCTURE COMPLEXED WITH PURINE RIBOSIDE AT PH 7.0=== |
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- | ==Overview==
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- | Adenosine deaminase, which catalyzes the irreversible hydrolytic deamination of adenosine nucleosides to inosine nucleosides and ammonia, is a key enzyme in purine metabolism and lymphoid development. The X-ray structures of murine adenosine deaminase with bound potent inhibitors (Ki values approximately 10(-13) M) (8R)-hydroxyl-2'-deoxycoformycin (pentostatin), a transition state analogue, and (6S)-hydroxyl-1,6-dihydropurine riboside, a reaction coordinate analogue, have been determined and refined to resolutions of 2.6 and 1.95 A, respectively. Crystals of both complexes were obtained at pH 7, where the enzyme is fully active, in an identical space group with the asymmetric unit containing four molecules. In addition to the very high degree of similarity between the four independent molecules in each complex structure, there is also considerable structural similarity of the complex with the dihydropurine riboside with that of an identical complex previously determined at pH 4.2 where the enzyme is 20% active. The interactions between the enzyme and the two analogues are extremely similar. These include the coordination of the 8R- or 6S-hydroxyl group of the analogues to the Zn2+ which mainly contributes to the strong potency and very high degree of stereospecificity of inhibition by these analogues. The interactions are further indicative of the structural and chemical requirements of substrates. These structures and recent site-directed mutagenesis have further shed light on the catalytic mechanism of the enzyme.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_9622483}}, adds the Publication Abstract to the page |
| + | (as it appears on PubMed at http://www.pubmed.gov), where 9622483 is the PubMed ID number. |
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| + | {{ABSTRACT_PUBMED_9622483}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Hydrolase]] | | [[Category: Hydrolase]] |
| [[Category: Purine riboside]] | | [[Category: Purine riboside]] |
- | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 09:48:18 2008'' | + | |
| + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jun 30 16:06:54 2008'' |
Revision as of 13:06, 30 June 2008
Template:STRUCTURE 1a4m
ADA STRUCTURE COMPLEXED WITH PURINE RIBOSIDE AT PH 7.0
Template:ABSTRACT PUBMED 9622483
About this Structure
1A4M is a Single protein structure of sequence from Mus musculus. Full crystallographic information is available from OCA.
Reference
Complexes of adenosine deaminase with two potent inhibitors: X-ray structures in four independent molecules at pH of maximum activity., Wang Z, Quiocho FA, Biochemistry. 1998 Jun 9;37(23):8314-24. PMID:9622483
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