Louis Katz, Ken-ichi Tomita, Alexander Rich
Sep 1, 1965
Citations
0
Influential Citations
54
Citations
Journal
Journal of molecular biology
Abstract
9-Ethyladenine and 1-methyl-5-bromouracil crystallize together in a 1:1 complex. The molecular structure of this complex was solved by analysis of 3-dimensional X-ray diffraction data. The two molecules form a nearly planar hydrogen-bonded pair, connected by two hydrogen bonds, N-H…N from the uracil N3 to the adenine imidazole N7 and N-H…O from the adenine amino group nitrogen N6 to the uracil O2. The hydrogen-bonded pairs are connected to pairs in neighboring unit cells through additional hydrogen bonds. The crystal structure has an unusual disordering feature. Approximately 6% of the uracil derivatives have an alternative hydrogen bonding to the adenine residue involving the carbonyl oxygen O4 instead of O2. The effect of the bromine atom on the hydrogen-bonding interaction as well as its possible mode of action in mutagenesis are discussed.