The extracellular transport signal of the Vibrio cholerae endochitinase (ChiA) is a structural motif located between amino acids 75 and 555.
The extracellular transport signal of the Vibrio cholerae endochitinase (ChiA) is a structural motif located between amino acids 75 and 555.
复制标题
霍乱弧菌内切几丁质酶 (ChiA) 的胞外转运信号是位于氨基酸 75 和 555 之间的结构基序。
DOI：
10.1128/jb.184.8.2225-2234.2002
复制
发表时间：
2002
影响因子：
3.2
通讯作者：
Connell,TerryD
中科院分区：
文献类型：
--
作者：
Folster,JasonP;Connell,TerryD
ChiA, an 88-kDa endochitinase encoded by thechiAgene of the gram-negative enteropathogenVibrio cholerae,is secreted via theeps-encoded main terminal branch of the general secretory pathway (GSP), a mechanism which also transports cholera toxin. To localize the extracellular transport signal of ChiA that initiates transport of the protein through the GSP, a chimera comprised of ChiA fused at the N terminus with the maltose-binding protein (MalE) ofEscherichia coliand fused at the C terminus with a 13-amino-acid epitope tag (E-tag) was expressed in strain 569B(chiA::Kanr), achiA-deficient but secretion-competent mutant ofV. cholerae. Fractionation studies revealed that blockage of the natural N terminus and C terminus of ChiA did not prevent secretion of the MalE-ChiA-E-tag chimera. To locate the amino acid sequences which encoded the transport signal, a series of truncations of ChiA were engineered. Secretion of the mutant polypeptides was curtailed only when ChiA was deleted from the N terminus beyond amino acid position 75 or from the C terminus beyond amino acid 555. A mutant ChiA comprised of only those amino acids was secreted by wild-typeV. choleraebut not by anepsDmutant, establishing that amino acids 75 to 555 independently harbored sufficient structural information to promote secretion by the GSP ofV. cholerae. Cys77 and Cys537, two cysteines located just within the termini of ChiA(75-555), were not required for secretion, indicating that those residues were not essential for maintaining the functional activity of the ChiA extracellular transport signal.
