Immunological cross-reactivity of mycobacterial topoisomerase I and divergence from other bacteria.
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.
Leelaram
Majety Naga
MN
Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India; Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
Bhat
Anuradha Gopal
AG
Suneetha
Nunna
N
Nagaraja
Valakunja
V
Manjunath
Ramanathapuram
R
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
D000911:Antibodies, Monoclonal; D009841:Oligonucleotides; D004264:DNA Topoisomerases, Type I