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Role of DegP for two‐partner secretion in Bordetella
Author(s) -
Baud C.,
Hodak H.,
Willery E.,
Drobecq H.,
Locht C.,
Jamin M.,
JacobDubuisson F.
Publication year - 2009
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2009.06860.x
Subject(s) - periplasmic space , biology , bacterial outer membrane , secretion , chaperone (clinical) , groel , microbiology and biotechnology , bordetella pertussis , protein folding , biochemistry , bacteria , escherichia coli , gene , genetics , medicine , pathology
Summary Sorting of proteins destined to the surface or the extracellular milieu is mediated by specific machineries, which guide the protein substrates towards the proper route of secretion and determine the compartment in which folding occurs. In Gram‐negative bacteria, the two‐partner secretion (TPS) pathway is dedicated to the secretion of large proteins rich in β‐helical structure. The secretion of the filamentous haemagglutinin (FHA), a 230 kDa adhesin of Bordetella pertussis , represents a model TPS system. FHA is exported by the Sec machinery and transits through the periplasm in an extended conformation. From there it is translocated across the outer membrane by its dedicated transporter FhaC to finally fold into a long β‐helix at the cell surface in a progressive manner. In this work, we show that B. pertussis lacking the periplasmic chaperone/protease DegP has a strong growth defect at 37°C, and the integrity of its outer membrane is compromised. While both phenotypes are significantly aggravated by the presence of FHA, the chaperone activity of DegP markedly alleviates the periplasmic stress. In vitro , DegP binds to non‐native FHA with high affinity. We propose that DegP chaperones the extended FHA polypeptide in the periplasm and is thus involved in the TPS pathway.