Viswamitra M A, Seshadri T P, Post M L, Kennard O
Nature. 1975 Dec 11;258(5535):497-501. doi: 10.1038/258497a0.
The nucleotide coenzyme cytidine-5'-diphospho-choline is highly folded. The CMP-5' parts of the molecules in the crystal structure are strongly linked by metal ligation and hydrogen bonds leaving the phosphoryl-choline residues relatively free. Cytidine-5'-diphosphoric acid exists as a zwitterion with N31 protonated. The P-O bond lengths from the anhydride bridging oxygen in the pyrophosphate are significantly different.
核苷酸辅酶胞苷-5'-二磷酸胆碱高度折叠。晶体结构中分子的CMP-5'部分通过金属配位和氢键紧密相连，使得磷酰胆碱残基相对自由。胞苷-5'-二磷酸以N31质子化的两性离子形式存在。来自焦磷酸中酸酐桥连氧的P-O键长度有显著差异。
