Recognition of GT mismatches by Vsr mismatch endonuclease
Fox, K.R., Allinson, S.L., Sahagun-Krause, H. and Brown, T. (2000) Recognition of GT mismatches by Vsr mismatch endonuclease. Nucleic Acids Research, 28, (13), 2535-2540. (doi:10.1093/nar/28.13.2535).
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The Vsr mismatch endonuclease recognises the sequence CTWGG (W = A or T) in which the underlined thymine is paired with guanine and nicks the DNA backbone on the 5′-side of the mispaired thymine. By using base analogues of G and T we have explored the functional groups on the mismatch pair which are recognised by the enzyme. Removal of the thymine 5-methyl group causes a 60% reduction in activity, while removing the 2-amino group of guanine reduces cleavage by 90%. Placing 2-aminopurine or nebularine opposite T generates mismatches which are cut at a much lower rate (0.1%). When either base is removed, generating a pseudoabasic site (1′,2′-dideoxyribose), the enzyme still produces site-specific cleavage, but at only 1% of the original rate. Although TT and CT mismatches at this position are cleaved at a low rate (~1%), mismatches with other bases (such as GA and AC) and Watson–Crick base pairs are not cleaved by the enzyme. There is also no cleavage when the mismatched T is replaced with difluorotoluene.
|Keywords:||escherichia-coli k-12, short patch repair, cytosine methylation, crystal-structure, dna duplex, gene, 5-methyl-cytosine, difluorotoluene, cleavage, adenine|
|Subjects:||Q Science > QD Chemistry
Q Science > QH Natural history > QH301 Biology
|Divisions:||University Structure - Pre August 2011 > School of Chemistry
|Date Deposited:||19 Jan 2006|
|Last Modified:||27 Mar 2014 18:08|
|RDF:||RDF+N-Triples, RDF+N3, RDF+XML, Browse.|
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