title: Model for interactions of amino acid side chains with Watson-Crick base pair of guanine and cytosine: crystal structure of 9-(2-carbamoylethyl)guanine and 1-methylcytosine complex.
abstract: As a model of interaction between the guanine-cytosine base pair and carbamoyl group, the crystal structure of 9-(2-carbamoylethyl)guanine-1-methylcytosine complex has been studied by X-ray method. The crystal data are a = 8.540 (1) A, b = 12.693 (3) A, c = 14.249 (2) A, beta = 94.02 (1) degrees, space group P21/c, Z = 4, dm = 1.50, dc = 1.49 g cm-3, and R = 0.10 for 1035 reflections. The bases form a Watson-Crick pair, and the carbamoyl group is hydrogen bonded with O(6) of guanine and N(4) of cytosine in the adjacent pairs. A structural correlation has been found between the hydrogen-bonding pattern and the secondary structural fitting of alpha-helical segment with B-form DNA.
mesh_terms: D001216:Asparagine; D003461:Crystallography; D003596:Cytosine / Q000031:analogs & derivatives; D004247:DNA; D004268:DNA-Binding Proteins; D005973:Glutamine; D006147:Guanine / Q000031:analogs & derivatives; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008961:Models, Structural; D009690:Nucleic Acid Conformation
chemical_list: D004268:DNA-Binding Proteins; D005973:Glutamine; C031532:1-methylcytosine; D006147:Guanine; D001216:Asparagine; D003596:Cytosine; D004247:DNA