Assembly of the type two secretion system in Aeromonas hydrophila involves direct interaction between the periplasmic domains of the assembly factor ExeB and the secretin ExeD.

The type two secretion system is a large, trans-envelope apparatus that secretes toxins across the outer membrane of many Gram-negative bacteria. In Aeromonas hydrophila, ExeA interacts with peptidoglycan and forms a heteromultimeric complex with ExeB that is required for assembly of the ExeD secret...

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Main Authors: Elizabeth M Vanderlinde, Su Zhong, Gang Li, Dariusz Martynowski, Pawel Grochulski, S Peter Howard
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2014-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC4098917?pdf=render
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spelling doaj-ba0750d83ae14f6d9247a77f353968152020-11-25T01:18:39ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-0197e10203810.1371/journal.pone.0102038Assembly of the type two secretion system in Aeromonas hydrophila involves direct interaction between the periplasmic domains of the assembly factor ExeB and the secretin ExeD.Elizabeth M VanderlindeSu ZhongGang LiDariusz MartynowskiPawel GrochulskiS Peter HowardThe type two secretion system is a large, trans-envelope apparatus that secretes toxins across the outer membrane of many Gram-negative bacteria. In Aeromonas hydrophila, ExeA interacts with peptidoglycan and forms a heteromultimeric complex with ExeB that is required for assembly of the ExeD secretin of the secretion system in the outer membrane. While the peptidoglycan-ExeAB (PG-AB) complex is required for ExeD assembly, the assembly mechanism remains unresolved. We analyzed protein-protein interactions to address the hypothesis that ExeD assembly in the outer membrane requires direct interaction with the PG-AB complex. Yeast and bacterial two hybrid analyses demonstrated an interaction between the periplasmic domains of ExeB and ExeD. Two-codon insertion mutagenesis of exeD disrupted lipase secretion, and immunoblotting of whole cells demonstrated significantly reduced secretin in mutant cells. Mapping of the two-codon insertions and deletion analysis showed that the ExeB-ExeD interaction involves the N0 and N1 subdomains of ExeD. Rotational anisotropy using the purified periplasmic domains of ExeB and ExeD determined that the apparent dissociation constant of the interaction is 1.19±0.16 µM. These results contribute important support for a putative mechanism by which the PG-AB complex facilitates assembly of ExeD through direct interaction between ExeB and ExeD. Furthermore, our results provide novel insight into the assembly function of ExeB that may contribute to elucidating the role of homologous proteins in secretion of toxins from other Gram negative pathogens.http://europepmc.org/articles/PMC4098917?pdf=render
collection DOAJ
language English
format Article
sources DOAJ
author Elizabeth M Vanderlinde
Su Zhong
Gang Li
Dariusz Martynowski
Pawel Grochulski
S Peter Howard
spellingShingle Elizabeth M Vanderlinde
Su Zhong
Gang Li
Dariusz Martynowski
Pawel Grochulski
S Peter Howard
Assembly of the type two secretion system in Aeromonas hydrophila involves direct interaction between the periplasmic domains of the assembly factor ExeB and the secretin ExeD.
PLoS ONE
author_facet Elizabeth M Vanderlinde
Su Zhong
Gang Li
Dariusz Martynowski
Pawel Grochulski
S Peter Howard
author_sort Elizabeth M Vanderlinde
title Assembly of the type two secretion system in Aeromonas hydrophila involves direct interaction between the periplasmic domains of the assembly factor ExeB and the secretin ExeD.
title_short Assembly of the type two secretion system in Aeromonas hydrophila involves direct interaction between the periplasmic domains of the assembly factor ExeB and the secretin ExeD.
title_full Assembly of the type two secretion system in Aeromonas hydrophila involves direct interaction between the periplasmic domains of the assembly factor ExeB and the secretin ExeD.
title_fullStr Assembly of the type two secretion system in Aeromonas hydrophila involves direct interaction between the periplasmic domains of the assembly factor ExeB and the secretin ExeD.
title_full_unstemmed Assembly of the type two secretion system in Aeromonas hydrophila involves direct interaction between the periplasmic domains of the assembly factor ExeB and the secretin ExeD.
title_sort assembly of the type two secretion system in aeromonas hydrophila involves direct interaction between the periplasmic domains of the assembly factor exeb and the secretin exed.
publisher Public Library of Science (PLoS)
series PLoS ONE
issn 1932-6203
publishDate 2014-01-01
description The type two secretion system is a large, trans-envelope apparatus that secretes toxins across the outer membrane of many Gram-negative bacteria. In Aeromonas hydrophila, ExeA interacts with peptidoglycan and forms a heteromultimeric complex with ExeB that is required for assembly of the ExeD secretin of the secretion system in the outer membrane. While the peptidoglycan-ExeAB (PG-AB) complex is required for ExeD assembly, the assembly mechanism remains unresolved. We analyzed protein-protein interactions to address the hypothesis that ExeD assembly in the outer membrane requires direct interaction with the PG-AB complex. Yeast and bacterial two hybrid analyses demonstrated an interaction between the periplasmic domains of ExeB and ExeD. Two-codon insertion mutagenesis of exeD disrupted lipase secretion, and immunoblotting of whole cells demonstrated significantly reduced secretin in mutant cells. Mapping of the two-codon insertions and deletion analysis showed that the ExeB-ExeD interaction involves the N0 and N1 subdomains of ExeD. Rotational anisotropy using the purified periplasmic domains of ExeB and ExeD determined that the apparent dissociation constant of the interaction is 1.19±0.16 µM. These results contribute important support for a putative mechanism by which the PG-AB complex facilitates assembly of ExeD through direct interaction between ExeB and ExeD. Furthermore, our results provide novel insight into the assembly function of ExeB that may contribute to elucidating the role of homologous proteins in secretion of toxins from other Gram negative pathogens.
url http://europepmc.org/articles/PMC4098917?pdf=render
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