Functional Analysis of the Minimal Twin-Arginine Translocation System Components from Streptococcus thermophilus CGMCC 7.179 in Escherichia coli DE3.
The twin-arginine translocation (Tat) system, which is used for folded protein secretion, is rare in lactic acid bacteria (LAB). Previously, a Tat system composed of TatASand TatCSsubunits (the subscript S denotes a Streptococcus thermophilus origin) was identified in S. thermophilus CGMCC 7.179. In the present study, the tatASand tatCSgenes were cloned and functionally analyzed in Escherichia coli DE3 tat-deficient mutants. The E. coli tatABCDE-deficient mutant complemented with tatCSASexhibited shortened cellular chains, but its ability to grow in the presence of sodium dodecyl sulfate (SDS) was not restored, suggesting that the S. thermophilus Tat system could partially replace that of E. coli. Surprisingly, the E. coli tatABE-deficient mutant complemented with tatASand the E. coli tatC-deficient mutant complemented with tatCSdisplayed relatively normal cellular morphology and enhanced tolerance to SDS. These results suggest that TatASand TatCScould serve as active protein translocases in E. coli DE3 tat-deficient mutants. Moreover, TatASacted as a bifunctional subunit to fulfill the roles of both TatA and TatB of E. coli DE3. Thus, this minimal Tat system would be a promising candidate to translocate recombinant proteins in LAB.
State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nanlu, Jinan, 250100, People's Republic of China.|College of Food Science and Technology, Yangzhou University, Yangzhou, People's Republic of China.|Key Laboratory of Dairy Biotechnology and Safety Control, Yangzhou, People's Republic of China.
Chenchen
C
Zhang
State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nanlu, Jinan, 250100, People's Republic of China.
Tingting
T
Guo
State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nanlu, Jinan, 250100, People's Republic of China.
Yongping
Y
Xin
State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nanlu, Jinan, 250100, People's Republic of China.
Susu
S
Zhang
State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nanlu, Jinan, 250100, People's Republic of China.
Xudong
X
Ouyang
College of Food Science and Technology, Yangzhou University, Yangzhou, People's Republic of China.|Key Laboratory of Dairy Biotechnology and Safety Control, Yangzhou, People's Republic of China.
Ruixia
R
Gu
State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nanlu, Jinan, 250100, People's Republic of China. kongjian@sdu.edu.cn.
Jian
J
Kong
D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000235:genetics*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D017353:Gene Deletion; D005816:Genetic Complementation Test; D026901:Membrane Transport Proteins / Q000235:genetics*; D021381:Protein Transport / Q000235:genetics*; D016415:Sequence Alignment; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D048249:Streptococcus thermophilus / Q000235:genetics*; D000069294:Twin-Arginine-Translocation System / Q000235:genetics* / Q000378:metabolism
D002352:Carrier Proteins; D026901:Membrane Transport Proteins; D000069294:Twin-Arginine-Translocation System; D012967:Sodium Dodecyl Sulfate
Complementation; Function; Streptococcus thermophilus; Tat system