Parallel DNA Constrained by“CC^+Clamps”  

作　　者：LIU Ke-liang H.Todd Miles Frank B.Howard Joe Frazier V.Sasisekharan 

机构地区：[1]Laboratory of Molecular Biology,NIDDK,National Institutes of Health,Bethesda,Maryland,20892,USA

出　　处：《Chemical Research in Chinese Universities》1999年第2期42-47,共6页高等学校化学研究(英文版)

摘　　要：Parallel DNA helices with reverse WatsonCrick pairing have been described in several papers.It has been pointed out,however,that the parallel structures may also be in equilibrium with antiparallel WatsonCrick helices due to their closely similar properties.To avoid the problem we have prepared and characterized DNA helices which are constrained to possess parallel polarity by two dC residues,or CC+clamps,at both the ends of AT oligomer chains.The residues are hemiprotonated below neutral pH,forming two stable CC+base pairs with three hydrogen bonds at each end of the helix.The physical properties of these constructs can then be used to calibrate those of duplexes having the same sequences but lacking the terminal C residues.Though recent studies indicate that dC acid selfstructures are fourstranded with intercalated bases,gel electrophoresis indicates that these structures are not present in the molecules described here.ＩｎｔｒｏｄｕｃｔｉｏｎＩｎａｄｄｉｔｉｏｎｔｏｔｈｅｆａｍｉｌｉａｒａｎｔｉｐａｒａｌｅｌＷａｔｓｏｎ－Ｃｒｉｃｋｄｕｐｌｅｘｅｓ，ｉｔｉｓａｌｓｏｐｏｓｓｉｂｌｅｔｏｆｏｒｍｐａｒａｌｅｌＤＮＡｈｅｔｅｒｏｄｕｐｌｅｘｅｓｗｉｔｈｒｅｖｅｒｓｅＷ...

关 键 词：Parallel DNA helices Reverse Watson-Crick pairing CC+ base pair Oligonucleotide helices  Reverse WatsonCrick pairing  CC+ base pair  Oligonucleotide 

分 类 号：O629.74[理学—有机化学]