Recognition of a nucleic acid base by tryptophan-containing peptides: spectroscopic comparison of the interaction of Trp-Gly-Gly-Glu and Trp-Gly-Gly-Gln with 7-methylguanine base.
As a part of a study to elucidate the functional difference between Glu and Gln side-chains in terms of the recognition of guanine base by tryptophan-containing peptides via cooperative stacking and hydrogen-bond pairing interactions, the binding of 7-methylguanine to Trp-Gly-Gly-Glu and Trp-Gly-Gly-Gln was examined by fluorescence and 1H-NMR methods. Comparison of fluorescence experiments showed a binding preference for Trp-Gly-Gly-Glu over Trp-Gly-Gly-Gln. The analyses of the downfield and upfield shifts of the C2 amino and N7 methyl protons of 7-methylguanine base showed there was hydrogen-bond pairing of Glu and Gln side chains with the base and a stacking interaction of the Trp residue with the base, respectively. However, the hydrogen-bond pairing was more effective in the case of the Glu residue than the Gln residue, indicating the preference of the carboxyl group over the carbamoyl group to form hydrogen-bond pairing with the guanine base.
Ishida
T
T
Department of Physical Chemistry, Osaka University of Pharmaceutical Sciences, Japan.
Toda
Y
Y
Tarui
M
M
Doi
M
M
Inoue
M
M
D000595:Amino Acid Sequence; D006147:Guanine / Q000031:analogs & derivatives* / Q000737:chemistry; D006860:Hydrogen Bonding; D008969:Molecular Sequence Data; D009696:Nucleic Acids / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D014364:Tryptophan / Q000737:chemistry*
D009696:Nucleic Acids; D010455:Peptides; D006147:Guanine; C008450:7-methylguanine; D014364:Tryptophan