Title: Improving Arsenic Tolerance of Pyrococcus furiosus by Heterologous Expression of a Respiratory Arsenate Reductase

Abstract

Arsenate is a notorious toxicant that is known to disrupt multiple biochemical pathways. Many microorganisms have developed mechanisms to detoxify arsenate using the ArsC-type arsenate reductase, and some even use arsenate as a terminal electron acceptor for respiration involving arsenate respiratory reductase (Arr). ArsC-type reductases have been studied extensively, but the phylogenetically unrelated Arr system is less investigated and has not been characterized from Archaea. Here, we heterologously expressed the genes encoding Arr from the crenarchaeon Pyrobaculum aerophilum in the euryarchaeon Pyrococcus furiosus, both of which grow optimally near 100°C. Recombinant P. furiosus was grown on molybdenum (Mo)- or tungsten (W)-containing medium, and two types of recombinant Arr enzymes were purified, one containing Mo (Arr-Mo) and one containing W (Arr-W). Purified Arr-Mo had a 140-fold higher specific activity in arsenate [As(V)] reduction than Arr-W, and Arr-Mo also reduced arsenite [As(III)]. The P. furiosus strain expressing Arr-Mo (the Arr strain) was able to use arsenate as a terminal electron acceptor during growth on peptides. In addition, the Arr strain had increased tolerance compared to that of the parent strain to arsenate and also, surprisingly, to arsenite. Compared to the parent, the Arr strain accumulated intracellularly almost an order of magnitude moremore » arsenic when cells were grown in the presence of arsenite. Furthermore, x-ray absorption spectroscopy (XAS) results suggest that the Arr strain of P. furiosus improves its tolerance to arsenite by increasing production of less-toxic arsenate and nontoxic methylated arsenicals compared to that by the parent.« less

Authors:

Haja, Dominik K. ^[1]; Wu, Chang-Hao ^[1]; Ponomarenko, Olena ^[2]; Poole, Farris L. ^[1]; George, II, Graham N. ^[2]; Adams, Michael W. W.  ^[1]

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+ Show Author Affiliations

1. Univ. of Georgia, Athens, GA (United States)
2. Univ. of Saskatchewan, Saskatoon, SK (Canada)

Publication Date:

Thu Oct 15 00:00:00 EDT 2020

Research Org.:

Univ. of Georgia, Athens, GA (United States); Stanford Univ., CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1850239

Grant/Contract Number:  

FG05-95ER20175; AC02-76SF00515

Resource Type:

Accepted Manuscript

Journal Name:

Applied and Environmental Microbiology

Additional Journal Information:

Journal Volume: 86; Journal Issue: 21; Journal ID: ISSN 0099-2240

Publisher:

American Society for Microbiology

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; Biotechnology & Applied Microbiology; Microbiology