Nature VOL 171, page737. 2 April 1953
A Structure for Deoxyribo Nucleic Acid
脱氧核糖核苷酸的结构
We wish to suggest a structure for the salt of deoxyribo nucleic acid (D.N.A.). This structure has novel features which are of considerable biological interest.
A structure for nucleic acid has already been propod by Pauling and Corey (1). They kindly made their manuscript available to us in advance of publication.
Their model consists of three intertwined chains, with the phosphates near the fibre axis, and the bas on the outside.
我们想推测出DNA结晶的结构。这些结构有许多新的为很多生物学家所吸引的特点.Pauling and Corey已经提出过核苷酸的一个结构.他们在出版以前慷慨的把他们的手稿给我们看过。他们的模型由三条相互缠绕的链组成，磷酸基团靠近中心轴，而碱基在外面。
In our opinion, this structure is unsatisfactory for two reasons:
我们认为，这个模型有以下两个方面的不足
(1) We believe that the material which gives the X-ray diagrams is the salt, not the free acid. Without the acidic hydrogen atoms it is not clear what forces would hold the structure together, especially as the negatively charged phosphates near the axis will repel each other. (2) Some of the van der Waals distances appear to be too small.
1.我们相信是晶体这个材料产生的X-衍射图标，而不是自由的酸。如果没有酸性的氢原子就不能确定什么使这些结构结合在一起。2.一些范德华距离太小
Another three-chain structure has also been suggested by Frar (in the press). In his model the phosphates are on the outside and the bas on the inside, linked together by hydrogen bonds. This structure as described is rather ill-defined, and for this reason we shall not comment on it.
Frar（在出版社里）曾提出过另一个三链的结构模型。在他的模型中磷酸基团在外面，
碱基在里面，他们以氢键连接曾被描述为相当不好的定义，因此我们在这不做评论。
This figure is purely diagrammatic. The two ribbons symboli the two phosphate-sugar chains and the horizontal rods the pairs of bas holding the chains together. The vertical line marks the fibre axis.
这个图片是纯图示性质。两条带象征两个糖-磷酸链，水平棒象征将两条链连接在一起的碱基对。垂直的线象征中心轴
We wish to put forward a radically different structure for the salt of deoxyribo nucleic acid. This structure has two helical chains each coiled round the same axis (e diagram). We have made the usual chemical assumptions, namely, that each chain consists of phosphate diester groups joining ß-D-deoxyribofurano residues with 3',5' linkages.
我们想提出一个根本不同的脱氧核糖核苷酸晶体的结构。这一结构有两条螺旋的链，每条绕着同一中心轴盘绕（如图所示）。我们曾做过普通的化学假定，换句话说，每条链由在3’,5处将磷酸二酯基团加入到脱氧核呋喃糖中。
The two chains (but not their bas) are related by a dyad perpendicular to the fibre axis. Both chains follow right- handed helices, but owing to the dyad the quences of the atoms in the two chains run in opposite directions. Each chain looly rembles Furberg's (2) model No. 1; that is, the bas are on the inside of the helix and the phosphates on the outside. The configuration of the sugar and the atoms near it is clo to Furberg's 'standard configuration', the sugar being roughly perpendicular to the attached ba. There is a residue on each every 3.4 A. in the z-direction. We have assumed an angle of 36° between adjacent residues in the same chain, so that the structure repeats after 10 residues on each chain, that is, after 34 A. The distance of a ph
osphorus atom from the fibre axis is 10 A. As the phosphates are on the outside, cations have easy access to them.
这两条链（出了它们的碱基）被双垂线联系到中心轴。两条链都遵循右手螺旋，但是双的螺旋，所以两条链上的院子向相反的方向运动。每条链近似Furberg's 的模型1。那就是，碱基在螺旋的里面，磷酸基在外面。糖和它周围原子的结构近似Furberg的标准结构：糖与和它连接的碱基成垂直存在。在这个Z式的螺旋中每3.4A有一个残基。我们假定同一条链上相邻残基之间有36°的角，因此每条链上的结构每十个残基重复一次，也就是每升高34A重复一次。纤维轴上的磷原子的距离为10A。由于磷在螺旋的外面，所以阳离子更容易接触到它们。
The structure is an open one, and its water content is rather high. At lower water contents we would expect the bas to tilt so that the structure could become more compact.
这一结构是一个开放式的结构，并且它的水含量相当高。因为水含量低会致使碱基
倾斜，而水含量多会使结构紧凑。
The novel feature of the structure is the manner in which the two chains are held together by the purine and pyrimidine bas. The planes of the bas are perpendicular to the fibre axis.
The are joined together in pairs, a single ba from the other chain, so that the two lie side by
side with identical z-co-ordinates. One of the pair must be a purine and the other a pyrimidine for bonding to occur. The hydrogen bonds are made as follows : purine position 1 to pyrimidine position 1; purine position 6 to pyrimidine position 6.
这一结构的新特点是嘌呤和嘧啶碱基将两条链结合在一起。碱基平面与中心轴垂直，它们以成对的方式与另一条链上的单独碱基结合在一起，所以两条链能肩并肩地围绕理想的垂直坐标轴。碱基对必须一边是嘌呤另一边是嘧啶才能结合在一起。氢键以这样的方式成键：第一个嘌呤和第一个嘧啶结合在一起，第6个嘌呤和第6个嘧啶结合在一起。
If it is assumed that the bas only occur in the structure in the most plausible tautomeric
forms (that is, with the keto rather than the enol configurations) it is found that only specific pairs of bas can bond together. The pairs are : adenine (purine) with thymine (pyrimidine), and guanine (purine) with cytosine (pyrimidine).
如果假设配对仅发生在最能发生互变异构的形式（即为酮式而不是烯醇式），我们发现只有特殊的碱基才能成对。这些对是：腺嘌呤和胸腺嘧啶配对，鸟嘌呤和胞嘧啶配对。
In other words, if an adenine forms one member of a pair, on either chain, then on the assumptions the other member must be thymine; similarly for guanine and cytosine. The quence of bas on a single chain does not appear to be restricted in any way. However, if only specific pairs of bas can be formed, it follows that if the quence of bas on one chain is given, then the quence on the other chain is automatically determined.
