【摘要】 运用计算机统计方法，对以木糖异构酶为主的几个蛋白质家族的核酸和氨基酸序列进行分析，发现密码于各位上的（G+C）％与编码序列的（G＋C）％成线性正相关。大多数氨基酸的含量与编码序列的（G＋C）％也存在相关性。按其相关性，将氨基酸分为正相关、负相关和不相关3类。对木糖异构酶氨基酸序列和酶的耐热性的统计发现，那些在统计学上显著的、可能提高蛋白质耐热性的氨基酸替换，往往伴随着编码序列中GC含量的上升。这提示了GC的水平上升，不仅能提高核酸的稳定性，而且有助于提高蛋白的耐热性。更多还原

【Abstract】 Stahstical analysis about amino acids and coding sequence of xylose isomerase were performed in a number of thermophiles and mesophiles. It was found that there are correlations between the (G+C) % of the coding sequence and that of 1st, 2nd and 3rd position of the code of amino acids. There were also positive (for hydrophobic amino acids) and negative (for hydrophilic amino acids) correlation between the content of individual amino acids in the enzyme protein and the (G+C) %of their respective coding sequence. It speaks for the notion that high content of (G+C) in the coding sequence tends to increase the thermostability of the corresponding protein. The results in the statistical analysis of amino acid substitutions leading to change in thermostability of the protein may also be interpreted in the same way. An increase in the (G+C) % of DNA of a bacterium can therefore not only increase the thermostability of DNA itself but its proteins as well. Evolutionary consequence concerning thermophily and coding system are discussed.更多还原