Amino acid sequence homology between the enzymic domains of diphtheria toxin and Pseudomonas aeruginosa exotoxin A
Amino acid sequence homology between the enzymic domains of diphtheria toxin and Pseudomonas aeruginosa exotoxin A
复制标题
DOI：
10.1111/j.1365-2958.1988.tb00031.x
复制
发表时间：
1988-03
影响因子：
3.6
通讯作者：
S. Carroll;R. Collier
中科院分区：
文献类型：
--
作者：
S. Carroll;R. Collier
尽管白喉毒素（DT）和铜绿假单胞菌外毒素A（ETA）的酶学性质相似，但它们在结构和作用上存在重大差异：因此，这两种蛋白质可能的进化相关性问题仍未得到解答。在这里，我们报告存在显着的氨基酸序列之间的同源性DT和ETA的酶结构域。序列的主要区段可以以高百分比的同一性和保守取代进行比对。ETA中的同源延伸形成了X射线晶体学结构中的大部分活性位点裂缝。这一证据表明，这些结构域至少已经从一个共同的祖先蛋白质中分化出来，并且活性位点残基已经高度保守。
Despite similarities In their enzymic properties, diphtheria toxin (DT) and exotoxin A (ETA) of Pseudomonas aeruginosa have major differences in structure and action: consequently, the question of possible evolutionary relatedness of these two proteins remains unanswered. Here we report the existence of significant amino acid sequence homology between the enzymic domain of DT and that of ETA. Iajor segments of sequence may be aligned with high percentages of identity and of conservative substitutions. The homologous stretches in ETA form much of the active‐site cleft in the X‐ray crystallographic structure. This evidence implies that these domains, at least, have diverged from a common ancestral protein and that active‐site residues have been strongly conserved.