title: Immunological cross-reactivity of mycobacterial topoisomerase I and divergence from other bacteria.
abstract: Mycobacterium smegmatis topoisomerase I exhibits several distinctive characteristics among all topoisomerases. The enzyme is devoid of Zn2+ fingers found typically in other bacterial type I topoisomerases and binds DNA in a site-specific manner. Using polyclonal antibodies, we demonstrate the high degree of relatedness of the enzyme across mycobacteria but not other bacteria. This absence of cross-reactivity from other bacteria indicates that mycobacterial topoisomerase I has diverged from Escherichia coli and other bacteria. We have investigated further the immunological properties of the enzyme by raising a panel of monoclonal antibodies that recognises different antigenically active regions of the enzyme and binds it with widely varied affinity. Inhibition of a C-terminal domain-specific antibody binding by enzyme-specific and non-specific oligonucleotides suggests the possibility of using these monoclonal antibodies to probe the structure, function and in vivo role of the enzyme.
authors: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India; Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
authors: Majety Naga
authors: MN
authors: Leelaram
authors: Anuradha Gopal
authors: AG
authors: Bhat
authors: Nunna
authors: N
authors: Suneetha
authors: Valakunja
authors: V
authors: Nagaraja
authors: Ramanathapuram
authors: R
authors: Manjunath
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015153:Blotting, Western; D003429:Cross Reactions / Q000276:immunology*; D004264:DNA Topoisomerases, Type I / Q000276:immunology* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D020102:Mycobacterium smegmatis / Q000145:classification / Q000201:enzymology* / Q000276:immunology; D009841:Oligonucleotides / Q000276:immunology; D013045:Species Specificity
chemical_list: D000911:Antibodies, Monoclonal; D009841:Oligonucleotides; D004264:DNA Topoisomerases, Type I