Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA, USA.
Virulence. 2010 Jul-Aug;1(4):319-24. doi: 10.4161/viru.1.4.12195.
To penetrate host cells through their membranes, pathogens use a variety of molecular components in which the presence of heptad repeat motifs seems to be a prevailing element. Heptad repeats are characterized by a pattern of seven, generally hydrophobic, residues. In order to initiate membrane fusion, viruses use glycoproteins-containing heptad repeats. These proteins are structurally and functionally similar to the SNARE proteins known to be involved in eukaryotic membrane fusion. SNAREs also display a heptad repeat motif called the "SNARE motif". As bacterial genomes are being sequenced, microorganisms also appear to be carrying membrane proteins resembling eukaryotic SNAREs. This category of SNARE-like proteins might share similar functions and could be used by microorganisms to either promote or block membrane fusion. Such a recurrence across pathogenic organisms suggests that this architectural motif was evolutionarily selected because it most effectively ensures the survival of pathogens within the eukaryotic environment.
为了穿透宿主细胞的细胞膜，病原体使用了多种分子成分，其中七肽重复基序的存在似乎是一个主要元素。七肽重复基序的特征是具有一种七肽重复模式，通常是疏水性残基。为了启动膜融合，病毒使用含有七肽重复基序的糖蛋白。这些蛋白质在结构和功能上与真核生物膜融合中已知的 SNARE 蛋白相似。SNARE 蛋白也显示出一种七肽重复基序，称为“SNARE 基序”。随着细菌基因组的测序，微生物似乎也携带类似于真核 SNARE 的膜蛋白。这一类 SNARE 样蛋白可能具有相似的功能，并可被微生物用来促进或阻止膜融合。这种在病原体中的反复出现表明，这种结构基序是通过进化选择的，因为它最有效地确保了病原体在真核环境中的生存。
