NONRANDOM UTILIZATION OF CODON PAIRS IN ESCHERICHIA-COLI
NONRANDOM UTILIZATION OF CODON PAIRS IN ESCHERICHIA-COLI
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DOI：
10.1073/pnas.86.10.3699
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发表时间：
1989-05-01
影响因子：
11.1
通讯作者：
HATFIELD, GW
中科院分区：
文献类型：
--
作者：
GUTMAN, GA;HATFIELD, GW
我们分析了大肠杆菌的蛋白质编码序列，发现密码子对的利用是高度偏倚的，反映了许多对的过度代表性或代表性不足，与他们的随机预期相比。这种效应超过了使用氨基酸对时的非随机性所带来的效应，这本身是非常明显的;当检查不相邻的密码子对时，这种效应要弱得多，当评估被两个或三个插入密码子分开的密码子对时，这种效应几乎消失。这种偏好似乎具有高度的方向性：任何参与许多非随机配对的密码子都倾向于产生代表性过强和代表性不足的配对，但优先作为左手或右手成员。我们显示了密码子对利用模式和基因表达水平之间的关系：相对于低水平表达的基因，编码高水平表达的蛋白质的基因往往包含更丰富，但更高度代表性不足的密码子对。 密码子对的非随机利用可能是其对翻译效率的影响的结果，这反过来可能与翻译核糖体的A和P位点处的相邻氨酰-tRNA异源受体的相容性有关。
We have analyzed protein-coding sequences of Escherichia coli and find that codon-pair utilization is highly biased, reflecting overrepresentation or underrepresentation of many pairs compared with their random expectation. This effect is over and above that contributed by nonrandomness in the use of amino acid pairs, which itself is highly evident; it is much weaker when nonadjacent codon pairs are examined and virtually disappears when pairs separated by two or three intervening codons are evaluated. There appears to be a high degree of directionality in this bias: any codon that participates in many nonrandom pairs tends to make both over- and underrepresented pairs, but preferentially as a left- or right-hand member. We show a relationship between codon-pair utilization patterns and levels of gene expression: genes encoding proteins expressed at high levels tend of contain more abundant, but more highly underrepresented, codon pairs, relative to genes expressed at low levels. The nonrandom utilization of codon pairs may be a consequent of their effects on translational efficiency, which in turn may be related to the compatibility of adjacent aminoacyl-tRNA isoacceptors at the A and P sites of a translating ribosome.