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| {{STRUCTURE_1wei| PDB=1wei | SCENE= }} | | {{STRUCTURE_1wei| PDB=1wei | SCENE= }} |
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| '''Catalytic Domain Of Muty From Escherichia Coli K20A Mutant Complexed To Adenine'''
| | ===Catalytic Domain Of Muty From Escherichia Coli K20A Mutant Complexed To Adenine=== |
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| ==Overview==
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| The Escherichia coli adenine DNA glycosylase, MutY, plays an important role in the maintenance of genomic stability by catalyzing the removal of adenine opposite 8-oxo-7,8-dihydroguanine or guanine in duplex DNA. Although the x-ray crystal structure of the catalytic domain of MutY revealed a mechanism for catalysis of the glycosyl bond, it appeared that several opportunistically positioned lysine side chains could participate in a secondary beta-elimination reaction. In this investigation, it is established via site-directed mutagenesis and the determination of a 1.35-A structure of MutY in complex with adenine that the abasic site (apurinic/apyrimidinic) lyase activity is alternatively regulated by two lysines, Lys142 and Lys20. Analyses of the crystallographic structure also suggest a role for Glu161 in the apurinic/apyrimidinic lyase chemistry. The beta-elimination reaction is structurally and chemically uncoupled from the initial glycosyl bond scission, indicating that this reaction occurs as a consequence of active site plasticity and slow dissociation of the product complex. MutY with either the K142A or K20A mutation still catalyzes beta and beta-delta elimination reactions, and both mutants can be trapped as covalent enzyme-DNA intermediates by chemical reduction. The trapping was observed to occur both pre- and post-phosphodiester bond scission, establishing that both of these intermediates have significant half-lives. Thus, the final spectrum of DNA products generated reflects the outcome of a delicate balance of closely related equilibrium constants. | | The line below this paragraph, {{ABSTRACT_PUBMED_15326180}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 15326180 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_15326180}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Tainer, J A.]] | | [[Category: Tainer, J A.]] |
| [[Category: Hydrolase]] | | [[Category: Hydrolase]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 13:32:24 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 09:49:31 2008'' |
