1YUA

C-TERMINAL DOMAIN OF ESCHERICHIA COLI TOPOISOMERASE I

Summary for 1YUA

• Entry DOI: 10.2210/pdb1yua/pdb
• Descriptor: TOPOISOMERASE I (1 entity in total)
• Functional Keywords: gene-regulating protein, dna binding protein
• Biological source: Escherichia coli
• Total number of polymer chains: 1
• Total formula weight: 13860.68

Authors

Yu, L.,Zhu, C.-X.,Tse-Dinh, Y.-C.,Fesik, S.W. (deposition date: 1995-03-02, release date: 1996-03-08, Last modification date: 2024-05-01)

Primary citation

Yu, L.,Zhu, C.X.,Tse-Dinh, Y.C.,Fesik, S.W.
Solution structure of the C-terminal single-stranded DNA-binding domain of Escherichia coli topoisomerase I.
Biochemistry, 34:7622-7628, 1995

PubMed Abstract: 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.

PubMed: 7779808
DOI: 10.1021/bi00023a008

Experimental method

SOLUTION NMR