Inactivation of PadR, the repressor of the phenolic acid stress response, by molecular interaction with Usp1, a universal stress protein from Lactobacillus plantarum, in Escherichia coli.
The phenolic acid decarboxylase gene padA is involved in the phenolic acid stress response (PASR) in gram-positive bacteria. In Lactobacillus plantarum, the padR gene encodes the negative transcriptional regulator of padA and is cotranscribed with a downstream gene, usp1, which encodes a putative universal stress protein (USP), Usp1, of unknown function. The usp1 gene is overexpressed during the PASR. However, the role and the mechanism of action of the USPs are unknown in gram-positive bacteria. Therefore, to gain insights into the role of USPs in the PASR; (i) a usp1 deletion mutant was constructed; (ii) the two genes padR and usp1 were coexpressed with padA under its own promoter as a reporter gene in Escherichia coli; and (iii) molecular in vitro interactions between the PadR, Usp1, and the padA promoter were studied. Although the usp1 mutant strain retained phenolic acid-dependent PAD activity, it displayed a greater sensitivity to strong acidic conditions compared to that of the wild-type strain. PadR cannot be inactivated directly by phenolic acid in E. coli recombinant cultures but is inactivated by Usp1 when the two proteins are coexpressed in E. coli. The PadR inactivation observed in recombinant E. coli cells was supported by electrophoretic mobility shift assays. Although Usp1 seems not to be absolutely required for the PASR, its capacity to inactivate PadR indicates that it could serve as an important mediator in acid stress response mechanisms through its capacity to interact with transcriptional regulators.
Gury
Jérôme
J
Laboratoire GPMA EA4181 IFR92, AgroSup Dijon ENSBANA, 1 Esplanade Erasme, Université de Bourgogne, Dijon F-21000, France.
Seraut
Hélène
H
Tran
Ngoc Phuong
NP
Barthelmebs
Lise
L
Weidmann
Stéphanie
S
Gervais
Patrick
P
Cavin
Jean-François
JF
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002262:Carboxy-Lyases / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D020868:Gene Silencing; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018869:Heat-Shock Response / Q000187:drug effects; D062385:Hydroxybenzoates / Q000494:pharmacology; D048191:Lactiplantibacillus plantarum / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D009154:Mutation; D016415:Sequence Alignment
D001426:Bacterial Proteins; D006360:Heat-Shock Proteins; D062385:Hydroxybenzoates; D002262:Carboxy-Lyases; C417714:phenolic acid decarboxylase; C017616:phenolic acid