Kang Hae Joo, Coulibaly Fasséli, Clow Fiona, Proft Thomas, Baker Edward N
Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland 1010, New Zealand.
Science. 2007 Dec 7;318(5856):1625-8. doi: 10.1126/science.1145806.
Many bacterial pathogens have long, slender pili through which they adhere to host cells. The crystal structure of the major pilin subunit from the Gram-positive human pathogen Streptococcus pyogenes at 2.2 angstroms resolution reveals an extended structure comprising two all-beta domains. The molecules associate in columns through the crystal, with each carboxyl terminus adjacent to a conserved lysine of the next molecule. This lysine forms the isopeptide bonds that link the subunits in native pili, validating the relevance of the crystal assembly. Each subunit contains two lysine-asparagine isopeptide bonds generated by an intramolecular reaction, and we find evidence for similar isopeptide bonds in other cell surface proteins of Gram-positive bacteria. The present structure explains the strength and stability of such Gram-positive pili and could facilitate vaccine development.
许多细菌病原体都有细长的菌毛，通过这些菌毛它们能够附着在宿主细胞上。革兰氏阳性人类病原体化脓性链球菌主要菌毛亚基的晶体结构在2.2埃分辨率下揭示了一种由两个全β结构域组成的延伸结构。这些分子在晶体中呈柱状排列，每个羧基末端与下一个分子的保守赖氨酸相邻。这个赖氨酸形成了连接天然菌毛中各亚基的异肽键，验证了晶体组装的相关性。每个亚基包含两个由分子内反应产生的赖氨酸-天冬酰胺异肽键，并且我们在革兰氏阳性细菌的其他细胞表面蛋白中发现了类似异肽键的证据。目前的结构解释了此类革兰氏阳性菌毛的强度和稳定性，并且可能有助于疫苗研发。
