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Mol Cells. 2016 Aug 31;39(8):594-602. doi: 10.14348/molcells.2016.0042. Epub 2016 Jul 25.

Enhancement of the Chaperone Activity of Alkyl Hydroperoxide Reductase C from Pseudomonas aeruginosa PAO1 Resulting from a Point-Specific Mutation Confers Heat Tolerance in Escherichia coli.

Author information

1
Research Division for Biotechnology, Advanced Radiation Technology Institute (ARTI), Korea Atomic Energy Research Institute (KAERI), Jeongeup 56212, Korea.
2
Fruit Vegetables Research Institute, Jellabuk-do Agricultural Research & Extension Services, Gunsan 54062, Korea.
3
Department of Radiation Biotechnology and Applied Radioisotope, Korea University of Science and Technology, Daejeon 34113, Korea.
4
Division of Applied Life Science (Brain Korea 21 Program), Gyeong-sang National University, Jinju 52828, Korea.
5
Department of Bioenergy Science and Technology, Chonnam National University, Gwangju 61186, Korea.
6
Department of Bioenvironmental Chemistry, Chonbuk National University, Jeonju 54896, Korea.

Abstract

Alkyl hydroperoxide reductase subunit C from Pseudomonas aeruginosa PAO1 (PaAhpC) is a member of the 2-Cys peroxiredoxin family. Here, we examined the peroxidase and molecular chaperone functions of PaAhpC using a site-directed mutagenesis approach by substitution of Ser and Thr residues with Cys at positions 78 and 105 located between two catalytic cysteines. Substitution of Ser with Cys at position 78 enhanced the chaperone activity of the mutant (S78C-PaAhpC) by approximately 9-fold compared with that of the wild-type protein (WT-PaAhpC). This increased activity may have been associated with the proportionate increase in the high-molecular-weight (HMW) fraction and enhanced hydrophobicity of S78C-PaAhpC. Homology modeling revealed that mutation of Ser(78) to Cys(78) resulted in a more compact decameric structure than that observed in WT-PaAhpC and decreased the atomic distance between the two neighboring sulfur atoms of Cys(78) in the dimer-dimer interface of S78C-PaAhpC, which could be responsible for the enhanced hydrophobic interaction at the dimer-dimer interface. Furthermore, complementation assays showed that S78C-PaAhpC exhibited greatly improved the heat tolerance, resulting in enhanced survival under thermal stress. Thus, addition of Cys at position 78 in PaAhpC modulated the functional shifting of this protein from a peroxidase to a chaperone.

KEYWORDS:

2-Cys peroxiredoxin; Pseudomonas aeruginosa; alkyl hydroperoxide reductase subunit C; chaperone; heat tolerance

PMID:
27457208
PMCID:
PMC4990751
DOI:
10.14348/molcells.2016.0042
[Indexed for MEDLINE]
Free PMC Article

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