The Arsenic Detoxification System in Corynebacteria: Basis and Application for Bioremediation and Redox Control.

Autor:	Mateos LM; University of León, León, Spain., Villadangos AF; University of León, León, Spain., de la Rubia AG; University of León, León, Spain., Mourenza A; University of León, León, Spain., Marcos-Pascual L; University of León, León, Spain., Letek M; University of León, León, Spain; University of Roehampton, London, United Kingdom., Pedre B; Vrije Universiteit Brussel, Brussels, Belgium; VIB Center for Structural Biology, Brussels, Belgium., Messens J; Vrije Universiteit Brussel, Brussels, Belgium; VIB Center for Structural Biology, Brussels, Belgium., Gil JA; University of León, León, Spain.
Jazyk:	angličtina
Zdroj:	Advances in applied microbiology [Adv Appl Microbiol] 2017; Vol. 99, pp. 103-137. Date of Electronic Publication: 2017 Mar 06.
DOI:	10.1016/bs.aambs.2017.01.001
Abstrakt:	Arsenic (As) is widespread in the environment and highly toxic. It has been released by volcanic and anthropogenic activities and causes serious health problems worldwide. To survive arsenic-rich environments, soil and saprophytic microorganisms have developed molecular detoxification mechanisms to survive arsenic-rich environments, mainly by the enzymatic conversion of inorganic arsenate (As V ) to arsenite (As III ) by arsenate reductases, which is then extruded by arsenite permeases. One of these Gram-positive bacteria, Corynebacterium glutamicum, the workhorse of biotechnological research, is also resistant to arsenic. To sanitize contaminated soils and waters, C. glutamicum strains were modified to work as arsenic "biocontainers." Two chromosomally encoded ars operons (ars1 and ars2) are responsible for As resistance. The genes within these operons encode for metalloregulatory proteins (ArsR1/R2), arsenite permeases (Acr3-1/-2), and arsenate reductases (ArsC1/C2/C1'). ArsC1/C2 arsenate reductases are coupled to the low molecular weight thiol mycothiol (MSH) and to the recently discovered mycoredoxin-1 (Mrx-1) present in most Actinobacteria. This MSH/Mrx-1 redox system protects cells against different forms of stress, including reactive oxygen species (ROS), metals, and antibiotics. ROS can modify functional sulfur cysteines by oxidizing the thiol (-SH) to a sulfenic acid (-SOH). These oxidation-sensitive protein cysteine thiols are redox regulated by the MSH/Mrx-1 couple in Corynebacterium and Mycobacterium. In summary, the molecular mechanisms involved in arsenic resistance system in C. glutamicum have paved the way for understanding the cellular response against oxidative stress in Actinobacteria. (Copyright © 2017 Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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