Differential roles of individual domains in selection of secretion route of a Streptococcus parasanguinis Serine-Rich Adhesin, fap1
Differential roles of individual domains in selection of secretion route of a Streptococcus parasanguinis Serine-Rich Adhesin, fap1
复制标题
DOI：
10.1128/jb.00748-07
复制
发表时间：
2007-11-01
影响因子：
3.2
通讯作者：
Fives-Taylor, Paula M.
中科院分区：
文献类型：
--
作者：
Chen, Qiang;Sun, Baiming;Fives-Taylor, Paula M.
菌毛相关蛋白I（Fap 1）是一种高分子量的糖基化表面粘附素，是副血链球菌菌毛生物发生和生物膜形成所必需的。成熟Fap 1的分泌依赖于SecA 2的存在，SecA 2是一种与SecA具有一定同源性但具有不同作用的蛋白质。将Fap 1的分泌引导至SecA 2依赖性分泌途径而不是SecA依赖性分泌途径的信号尚未被鉴定。在这项研究中，含有不同结构域的Fap 1变体在secA 2野生型和突变体背景中表达，并测试其通过SecA或SecA 2依赖性途径分泌的能力。在C末端存在或不存在细胞壁锚结构域（残基2531至2570）不改变Fap 1分泌途径的选择。Fap 1信号肽（残基I至68）足以支持经由SecA依赖性途径的异源蛋白的分泌，表明信号肽足以被SecA依赖性途径识别。SecA 2依赖性途径所需的Fap 1的最小序列包括N-末端信号肽、非重复区I（残基69至102）和非重复区11的一部分（残基169至342）。两个富含丝氨酸的重复区域（残基103至168和505至2530）对于Fap 1分泌不是必需的。然而，它们都通过SecA依赖性途径参与Fap 1分泌的特异性抑制。
Fimbria-associated protein I (Fap1) is a high-molecular-mass glycosylated surface adhesin required for fimbria biogenesis and biofilm formation in Streptococcus parasanguinis. The secretion of mature Fap1 is dependent on the presence of SecA2, a protein with some homology to, but with a different role from, SecA. The signals that direct the secretion of Fap1 to the SecA2-dependent secretion pathway rather than the SecA-dependent secretion pathway have not yet been identified. In this study, Fap1 variants containing different domains were expressed in both secA2 wild-type and mutant backgrounds and were tested for their ability to be secreted by the SecA- or SecA2-dependent pathway. The presence or absence of the cell wall anchor domain (residues 2531 to 2570) at the C terminus did not alter the selection of the Fap1 secretion route. The Fap1 signal peptide (residues I to 68) was sufficient to support the secretion of a heterologous protein via the SecA-dependent pathway, suggesting that the signal peptide was sufficient for recognition by the SecA-dependent pathway. The minimal sequences of Fap1 required for the SecA2-dependent pathway included the N-terminal signal peptide, nonrepetitive region I (residues 69 to 102), and part of nonrepetitive region 11 (residues 169 to 342). The two serine-rich repeat regions (residues 103 to 168 and 505 to 2530) were not required for Fap1 secretion. However, they were both involved in the specific inhibition of Fap1 secretion via the SecA-dependent pathway.