蛋白质序列和结构的保守性与其功能的关系

THE RELATIONS OF PROTEIN SEQUENCE AND STRUCTURAL CONSERVATION WITH FUNCTION

以蛋白质酪氨酸磷酸酶为模型，通过序列和结构的比较，对蛋白质序列、结构的保守性与其功能和进化的关系问题进行了研究。结果显示，虽然在酪氨酸磷酸酶超家族分子的序列中，仅有３个与其催化功能密切相关的残基是高度保守的，但它们功能结构域的核心拓扑结构却明显类似，其中存在着βαβ和βαβα２个保守的结构单元；此外，它们活性位点的拓扑结构也极其相似。因此，在保持蛋白质功能方面具有重要作用的残基是高度保守的，而具维持蛋白质结构作用的残基则是相对保守的。在进化过程中，蛋白质三维拓扑结构的保守性，似乎主要是体现在保持某些共同的特有二级结构单元和共同的折叠方式上。

The conservation in sequence and structure of protein tyrosine phosphatases has been analyzed by aligning their sequences and superposed their three dimensional topological structures.The results indicated that only three residues related closely to the function are conserved in sequence,but the core regions in their functional domains are strikingly similar in structure,and there are two conserved structural motifs, i.e ,βαβ and βαβα motifs.On the other hand, the topology of the active site in protein tyrosine phosphatases is also very similar.Thus,it is suggested that the very important residues for maintaining protein function are highly conserved,however,the residues for keeping protein structure are conservatively varied.In molecular evolution,three dimensional structural conservation seems to be mainly expressed in holding some common secondary structural elements and common fold.