Crystal structure of the heteromolecular chaperone, AscE-AscG, from the type III secretion system in Aeromonas hydrophila

Chiradip Chatterjee; Sundramurthy Kumar; Smarajit Chakraborty; Yih Wan Tan; Ka Yin Leung; J. Sivaraman; Yu Keung Mok

doi:10.1371/journal.pone.0019208

Crystal structure of the heteromolecular chaperone, AscE-AscG, from the type III secretion system in Aeromonas hydrophila

Chiradip Chatterjee, Sundramurthy Kumar, Smarajit Chakraborty, Yih Wan Tan, Ka Yin Leung, J. Sivaraman, Yu Keung Mok^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

12 Scopus citations

Abstract

Background: The putative needle complex subunit AscF forms a ternary complex with the chaperones AscE and AscG in the type III secretion system of Aeromonas hydrophila so as to avoid premature assembly. Previously, we demonstrated that the C-terminal region of AscG (residues 62-116) in the hetero-molecular chaperone, AscE-AscG, is disordered and susceptible to limited protease digestion. Methodology/Principal Findings: Here, we report the crystal structure of the ordered AscG_1-61 region in complex with AscE at 2.4 Å resolution. Helices α2 and α3 of AscE in the AscE-AscG_1-61 complex assumes a helix-turn-helix conformation in an anti-parallel fashion similar to that in apo AscE. However, in the presence of AscG, an additional N-terminal helix α1 in AscE (residues 4-12) is observed. PscG or YscG in the crystal structures of PscE-PscF-PscG or YscE-YscF-YscG, respectively, assumes a typical tetratricopeptide repeat (TPR) fold with three TPR repeats and one C-terminal capping helix. By comparison, AscG in AscE-AscG_1-61 comprises three anti-parallel helices that resembles the N-terminal TPR repeats in the corresponding region of PscG or YscG in PscE-PscF-PscG or YscE-YscF-YscG. Thermal denaturation of AscE-AscG and AscE-AscG_1-61 complexes demonstrates that the C-terminal disordered region does not contribute to the thermal stability of the overall complex. Conclusion/Significance: The N-terminal region of the AscG in the AscE-AscG complex is ordered and assumes a structure similar to those in the corresponding regions of PscE-PscG-PscF or YscE-YscF-YscG complexes. While the C-terminal region of AscG in the AscE-AscG complex is disordered and will assume its structure only in the presence of the substrate AscF. We hypothesize that AscE act as a chaperone of the chaperone to keep AscG in a stable but partially disordered state for interaction with AscF.

Original language	English
Article number	e19208
Journal	PLoS ONE
Volume	6
Issue number	4
DOIs	https://doi.org/10.1371/journal.pone.0019208
State	Published - 2011
Externally published	Yes

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@article{2ea789e55d834f1bbfecf11ca7a8144f,

title = "Crystal structure of the heteromolecular chaperone, AscE-AscG, from the type III secretion system in Aeromonas hydrophila",

abstract = "Background: The putative needle complex subunit AscF forms a ternary complex with the chaperones AscE and AscG in the type III secretion system of Aeromonas hydrophila so as to avoid premature assembly. Previously, we demonstrated that the C-terminal region of AscG (residues 62-116) in the hetero-molecular chaperone, AscE-AscG, is disordered and susceptible to limited protease digestion. Methodology/Principal Findings: Here, we report the crystal structure of the ordered AscG1-61 region in complex with AscE at 2.4 {\AA} resolution. Helices α2 and α3 of AscE in the AscE-AscG1-61 complex assumes a helix-turn-helix conformation in an anti-parallel fashion similar to that in apo AscE. However, in the presence of AscG, an additional N-terminal helix α1 in AscE (residues 4-12) is observed. PscG or YscG in the crystal structures of PscE-PscF-PscG or YscE-YscF-YscG, respectively, assumes a typical tetratricopeptide repeat (TPR) fold with three TPR repeats and one C-terminal capping helix. By comparison, AscG in AscE-AscG1-61 comprises three anti-parallel helices that resembles the N-terminal TPR repeats in the corresponding region of PscG or YscG in PscE-PscF-PscG or YscE-YscF-YscG. Thermal denaturation of AscE-AscG and AscE-AscG1-61 complexes demonstrates that the C-terminal disordered region does not contribute to the thermal stability of the overall complex. Conclusion/Significance: The N-terminal region of the AscG in the AscE-AscG complex is ordered and assumes a structure similar to those in the corresponding regions of PscE-PscG-PscF or YscE-YscF-YscG complexes. While the C-terminal region of AscG in the AscE-AscG complex is disordered and will assume its structure only in the presence of the substrate AscF. We hypothesize that AscE act as a chaperone of the chaperone to keep AscG in a stable but partially disordered state for interaction with AscF.",

author = "Chiradip Chatterjee and Sundramurthy Kumar and Smarajit Chakraborty and Tan, {Yih Wan} and Leung, {Ka Yin} and J. Sivaraman and Mok, {Yu Keung}",

year = "2011",

doi = "10.1371/journal.pone.0019208",

language = "英语",

volume = "6",

journal = "PLoS ONE",

issn = "1932-6203",

publisher = "Public Library of Science",

number = "4",

}

TY - JOUR

T1 - Crystal structure of the heteromolecular chaperone, AscE-AscG, from the type III secretion system in Aeromonas hydrophila

AU - Chatterjee, Chiradip

AU - Kumar, Sundramurthy

AU - Chakraborty, Smarajit

AU - Tan, Yih Wan

AU - Leung, Ka Yin

AU - Sivaraman, J.

AU - Mok, Yu Keung

PY - 2011

Y1 - 2011

N2 - Background: The putative needle complex subunit AscF forms a ternary complex with the chaperones AscE and AscG in the type III secretion system of Aeromonas hydrophila so as to avoid premature assembly. Previously, we demonstrated that the C-terminal region of AscG (residues 62-116) in the hetero-molecular chaperone, AscE-AscG, is disordered and susceptible to limited protease digestion. Methodology/Principal Findings: Here, we report the crystal structure of the ordered AscG1-61 region in complex with AscE at 2.4 Å resolution. Helices α2 and α3 of AscE in the AscE-AscG1-61 complex assumes a helix-turn-helix conformation in an anti-parallel fashion similar to that in apo AscE. However, in the presence of AscG, an additional N-terminal helix α1 in AscE (residues 4-12) is observed. PscG or YscG in the crystal structures of PscE-PscF-PscG or YscE-YscF-YscG, respectively, assumes a typical tetratricopeptide repeat (TPR) fold with three TPR repeats and one C-terminal capping helix. By comparison, AscG in AscE-AscG1-61 comprises three anti-parallel helices that resembles the N-terminal TPR repeats in the corresponding region of PscG or YscG in PscE-PscF-PscG or YscE-YscF-YscG. Thermal denaturation of AscE-AscG and AscE-AscG1-61 complexes demonstrates that the C-terminal disordered region does not contribute to the thermal stability of the overall complex. Conclusion/Significance: The N-terminal region of the AscG in the AscE-AscG complex is ordered and assumes a structure similar to those in the corresponding regions of PscE-PscG-PscF or YscE-YscF-YscG complexes. While the C-terminal region of AscG in the AscE-AscG complex is disordered and will assume its structure only in the presence of the substrate AscF. We hypothesize that AscE act as a chaperone of the chaperone to keep AscG in a stable but partially disordered state for interaction with AscF.

AB - Background: The putative needle complex subunit AscF forms a ternary complex with the chaperones AscE and AscG in the type III secretion system of Aeromonas hydrophila so as to avoid premature assembly. Previously, we demonstrated that the C-terminal region of AscG (residues 62-116) in the hetero-molecular chaperone, AscE-AscG, is disordered and susceptible to limited protease digestion. Methodology/Principal Findings: Here, we report the crystal structure of the ordered AscG1-61 region in complex with AscE at 2.4 Å resolution. Helices α2 and α3 of AscE in the AscE-AscG1-61 complex assumes a helix-turn-helix conformation in an anti-parallel fashion similar to that in apo AscE. However, in the presence of AscG, an additional N-terminal helix α1 in AscE (residues 4-12) is observed. PscG or YscG in the crystal structures of PscE-PscF-PscG or YscE-YscF-YscG, respectively, assumes a typical tetratricopeptide repeat (TPR) fold with three TPR repeats and one C-terminal capping helix. By comparison, AscG in AscE-AscG1-61 comprises three anti-parallel helices that resembles the N-terminal TPR repeats in the corresponding region of PscG or YscG in PscE-PscF-PscG or YscE-YscF-YscG. Thermal denaturation of AscE-AscG and AscE-AscG1-61 complexes demonstrates that the C-terminal disordered region does not contribute to the thermal stability of the overall complex. Conclusion/Significance: The N-terminal region of the AscG in the AscE-AscG complex is ordered and assumes a structure similar to those in the corresponding regions of PscE-PscG-PscF or YscE-YscF-YscG complexes. While the C-terminal region of AscG in the AscE-AscG complex is disordered and will assume its structure only in the presence of the substrate AscF. We hypothesize that AscE act as a chaperone of the chaperone to keep AscG in a stable but partially disordered state for interaction with AscF.

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U2 - 10.1371/journal.pone.0019208

DO - 10.1371/journal.pone.0019208

M3 - 文章

C2 - 21559439

AN - SCOPUS:79955744846

SN - 1932-6203

VL - 6

JO - PLoS ONE

JF - PLoS ONE

IS - 4

M1 - e19208

ER -

Crystal structure of the heteromolecular chaperone, AscE-AscG, from the type III secretion system in Aeromonas hydrophila

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