title: Binding specificity of post-activated neocarzinostatin chromophore drug-bulged DNA complex studied using electrospray ionization mass spectrometry.
abstract: Electrospray ionization mass spectrometry (ESI-MS) was employed to characterize the binding specificity of a bulged 22-mer DNA hairpin with a post-activated neocarzinostatin chromophore (NCS-Chrom) having two similar forms, where 2a has an H in a location for which 2b has it replaced by a CH2OH group. Specific binding of 2a to the bulged 22-mer DNA was observed whereas little binding was detected for 2a to non-bulged DNA 19-mer and 12-mer duplexes. The stoichiometry of the 22-mer DNA complex with 2a was determined to be predominantly 1:1. Substitution of hydrogen in 2a for the hydroxymethylene group in 2b dramatically reduced the binding strength to the 22-mer DNA. Little complex formation was observed for 2b and 22-mer DNA based upon the ESI-MS data, consistent with earlier fluorescence studies. The results indicate that ESI-MS can be a sensitive technique for probing conformational specificity in studies of biomolecular binding.
authors.affiliation: Environment Molecular Sciences Laboratory, National Laboratory, Richland, Washington 99352, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Gao
authors.forename: X
authors.initials: X
authors.lastname: Cheng
authors.forename: R D
authors.initials: RD
authors.lastname: Smith
authors.forename: C F
authors.initials: CF
authors.lastname: Yang
authors.forename: I H
authors.initials: IH
authors.lastname: Goldberg
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000378:metabolism*; D001483:Base Sequence; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D053281:Enediynes; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D009353:Zinostatin / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism
chemical_list: D000903:Antibiotics, Antineoplastic; D053281:Enediynes; C032372:neocarzinostatin chromophore; D004247:DNA; D009353:Zinostatin