Qy. Gao et al., BINDING-SPECIFICITY OF POST-ACTIVATED NEOCARZINOSTATIN CHROMOPHORE DRUG-BULGED DNA COMPLEX STUDIED USING ELECTROSPRAY-IONIZATION MASS-SPECTROMETRY, Journal of mass spectrometry., 31(1), 1996, pp. 31-36
Electrospray ionization mass spectrometry (ESI-MS) was employed to cha
racterize the binding specificity of a bulged 22-mer DNA hairpin with
a post-activated neocarzinostatin chromophore (NCS-Chrom) having two s
imilar forms, where 2a has an H in a location for which 2b has it repl
aced 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 c
omplex with 2a was determined to be predominantly 1:1. Substitution of
hydrogen in 2a for the hydroxymethylene group in 2b dramatically redu
ced the binding strength to the 22-mer DNA. Little complex formation w
as observed for 2b and 22-mer DNA based upon the ESI-MS data, consiste
nt with earlier fluorescence studies, The results indicate that ESI-MS
can be a sensitive technique for probing conformational specificity i
n studies of biomolecular binding.