Gao Q, Cheng X, Smith R D, Yang C F, Goldberg I H
Environment Molecular Sciences Laboratory, National Laboratory, Richland, Washington 99352, USA.
J Mass Spectrom. 1996 Jan;31(1):31-6. doi: 10.1002/(SICI)1096-9888(199601)31:1<31::AID-JMS244>3.0.CO;2-I.
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.
