1yua
From Proteopedia
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C-TERMINAL DOMAIN OF ESCHERICHIA COLI TOPOISOMERASE I
Overview
Escherichia coli DNA topoisomerase I catalyzes the interconversion of, different topological forms of DNA. In this paper we describe NMR studies, of a 14K C-terminal fragment of this enzyme that binds preferentially to, single-stranded DNA and enhances the enzyme's ability to relax negatively, supercoiled DNA under high salt conditions. The 1H, 13C, and 15N, resonances of the protein were assigned from a number of heteronuclear, multidimensional NMR experiments, and the three-dimensional structure of, the protein was determined from a total of 2188 NMR-derived restraints., The root-mean-square deviation about the mean coordinate positions for, residues 13-120 is 0.68 +/- 0.11 A for the backbone atoms and 1.09 +/-, 0.09 A for all heavy atoms. The overall fold, which consists of two, four-stranded beta-sheets separated by two helices, differs from other, DNA- and RNA-binding proteins such as gene 5, cold shock protein, and, hnRNP C. From an analysis of the changes in chemical shift upon the, addition of single-stranded DNA, the location of the oligonucleotide, binding site was determined. The binding site consists of a beta-sheet, containing positively charged and aromatic amino acids and, in spite of, its different structure, is similar to that found in other proteins that, bind single-stranded oligonucleotides.
About this Structure
1YUA is a Single protein structure of sequence from Escherichia coli. Active as DNA topoisomerase, with EC number 5.99.1.2 Full crystallographic information is available from OCA.
Reference
Solution structure of the C-terminal single-stranded DNA-binding domain of Escherichia coli topoisomerase I., Yu L, Zhu CX, Tse-Dinh YC, Fesik SW, Biochemistry. 1995 Jun 13;34(23):7622-8. PMID:7779808
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