title: Zorbamycin has a different DNA sequence selectivity compared with bleomycin and analogues.
abstract: Bleomycin (BLM) is used clinically in combination with a number of other agents for the treatment of several types of tumours. Members of the BLM family of drugs include zorbamycin (ZBM), phleomycin D1, BLM A2 and BLM B2. By manipulating the BLM biosynthetic machinery, we have produced two new BLM analogues, BLM Z and 6'-deoxy-BLM Z, with the latter exhibiting significantly improved DNA cleavage activity. Here we determined the DNA sequence specificity of BLM Z, 6'-deoxy-BLM Z and ZBM, in comparison with BLM, with high precision using purified plasmid DNA and our recently developed technique. It was found that ZBM had a different DNA sequence specificity compared with BLM and the BLM analogues. While BLM and the BLM analogues showed a similar DNA sequence specificity, with TGTA sequences as the main site of cleavage, ZBM exhibited a distinct DNA sequence specificity, with both TGTA and TGTG as the predominant cleavage sites. These differences in DNA sequence specificity are discussed in relation to the structures of ZBM, BLM and the BLM analogues. Our findings support the strategy of manipulating the BLM biosynthetic machinery for the production of novel BLM analogues, difficult to prepare by total synthesis; some of which could have beneficial cancer chemotherapeutic properties.
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: Jon K
authors.initials: JK
authors.lastname: Chen
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: Dong
authors.initials: D
authors.lastname: Yang
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: Ben
authors.initials: B
authors.lastname: Shen
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: Brett A
authors.initials: BA
authors.lastname: Neilan
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia. Electronic address: v.murray@unsw.edu.au.
authors.forename: Vincent
authors.initials: V
authors.lastname: Murray
mesh_terms: D001483:Base Sequence; D001761:Bleomycin / Q000031:analogs & derivatives / Q000737:chemistry*; D004247:DNA / Q000235:genetics; D006020:Glycopeptides / Q000737:chemistry / Q000235:genetics*; D015394:Molecular Structure; D010957:Plasmids
chemical_list: D006020:Glycopeptides; D001761:Bleomycin; D004247:DNA; C003787:zorbamycin
keywords: Anti-tumour agent; Bleomycin analogue; DNA cleavage; DNA sequence specificity; Zorbamycin