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Hoogsteen versus Watson‐Crick A‐T basepairing in DNA complexes of a new group of ‘quinomycin‐like’ antibiotics
Author(s) -
Searle Mark S.,
Wickham Geoffrey
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)80476-y
Subject(s) - deoxyribose , molecular structure of nucleic acids: a structure for deoxyribose nucleic acid , chemistry , glycosidic bond , dna , stereochemistry , base pair , crystallography , hydrogen bond , nucleobase , nuclear magnetic resonance spectroscopy , molecule , biochemistry , enzyme , organic chemistry
The interaction of a new group of ‘quinomycin‐like’ antibiotics with the DNA duplexes d(ACGT) 2 and d(GACGTC) 2 has been investigated in solution by 1 H NMR spectroscopy. By monitoring the intensity of intranucleotide base H6/H8 to deoxyribose H1'NOE cross‐peaks we conclude that the terminal A‐T basepairs flanking the CG bisintercalation site in the d(ACGT) 2 complex adopt the Hoogsteen bonding scheme, with the purine base in a syn conformation. By comparison in the d(GACGTC) 2 complex all glycosidic bond angles are anti , consistent with a preferred Watson‐Crick basepairing scheme. Both DNA duplexes appear to be significantly unwound compared with the ligand‐free DNAs. The data illustrate the influence of helical constraints on the stability of the Hoogsteen bonding scheme adjacent to the drug binding sites.