SecA is an essential component of the Sec protein secretion pathway in bacteria. Secretory proteins targeted to the Sec pathway by their N-terminal signal peptide bind to SecA, which couples binding and hydrolysis of adenosine triphosphate with movement of the secretory protein across the membrane-embedded SecYEG protein translocon. The phylogenetic diversity of bacteria raises the important question as to whether the region of SecA where the pre-protein binds has conserved sequence features that might impact the reaction mechanism of SecA. To address this question we established a large data set of SecA protein sequences and implemented a protocol to cluster and analyze these sequences according to features of two of the SecA functional domains, the protein binding domain and the nucleotide-binding domain 1. We identify remarkable sequence diversity of the protein binding domain, but also conserved motifs with potential role in protein binding. The N-terminus of SecA has sequence motifs that could help anchor SecA to the membrane. The overall sequence length and net estimated charge of SecA sequences depend on the organism.

SecA是细菌中Sec蛋白分泌途径的重要组成部分。靶向Sec的分泌蛋白通过其N端信号肽与SecA结合的途径，该结合使三磷酸腺苷的结合和水解与分泌蛋白跨膜嵌入SecYEG蛋白转运子的移动耦合。细菌的系统发育多样性提出了一个重要的问题，即前蛋白结合的SecA区域是否具有保守的序列特征，从而可能影响SecA的反应机制。为了解决这个问题，我们建立了一个庞大的SecA蛋白序列数据集，并根据两个SecA功能域（蛋白结合域和核苷酸结合域1）的特征实施了协议，对这些序列进行聚类和分析。蛋白质结合结构域的序列多样性，以及在蛋白质结合中具有潜在作用的保守基序。SecA的N端具有序列基序，可以帮助将SecA锚定在膜上。SecA序列的总序列长度和净估计电荷取决于生物体。