Dataset Information

Arsenite oxidase in complex with antimonite and arsenite oxyanions: Insights into the catalytic mechanism.

ABSTRACT: Arsenic contamination of groundwater is among one of the biggest health threats affecting millions of people in the world. There is an urgent need for efficient arsenic biosensors where the use of arsenic metabolizing enzymes can be explored. In this work, we have solved four crystal structures of arsenite oxidase (Aio) in complex with arsenic and antimony oxyanions and the structures determined correspond to intermediate states of the enzymatic mechanism. These structural data were complemented with density-functional theory calculations providing a unique view of the molybdenum active site at different time points that, together with mutagenesis data, enabled to clarify the enzymatic mechanism and the molecular determinants for the oxidation of As(III) to the less toxic As(V) species.

SUBMITTER: Engrola F

PROVIDER: S-EPMC10448176 | biostudies-literature | 2023 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Arsenite oxidase in complex with antimonite and arsenite oxyanions: Insights into the catalytic mechanism.

Engrola Filipa F Correia Márcia A S MAS Watson Cameron C Romão Carlos C CC Veiros Luis F LF Romão Maria João MJ Santos-Silva Teresa T Santini Joanne M JM

The Journal of biological chemistry 20230711 8

Arsenic contamination of groundwater is among one of the biggest health threats affecting millions of people in the world. There is an urgent need for efficient arsenic biosensors where the use of arsenic metabolizing enzymes can be explored. In this work, we have solved four crystal structures of arsenite oxidase (Aio) in complex with arsenic and antimony oxyanions and the structures determined correspond to intermediate states of the enzymatic mechanism. These structural data were complemented ...[more]

PMID: 37442232

Similar Datasets

Project description:Arsenic-resistant bacteria have evolved various efflux systems for arsenic resistance. Five arsenic efflux proteins, ArsB, Acr3, ArsP, ArsJ, and MSF1, have been reported. In this study, comprehensive analyses were performed to study the function of a putative major facilitator superfamily gene, arsK, and the regulation of arsK transcriptional expression in Agrobacterium tumefaciens GW4. We found that (i) arsK is located on an arsenic gene island in strain GW4. ArsK orthologs are widely distributed in arsenic-resistant bacteria and are phylogenetically divergent from the five reported arsenic efflux proteins, indicating that it may be a novel arsenic efflux transporter. (ii) Reporter gene assays showed that the expression of arsK was induced by arsenite [As(III)], antimonite [Sb(III)], trivalent roxarsone [Rox(III)], methylarsenite [MAs(III)], and arsenate [As(V)]. (iii) Heterologous expression of ArsK in an arsenic-hypersensitive Escherichia coli strain showed that ArsK was essential for resistance to As(III), Sb(III), Rox(III), and MAs(III) but not to As(V), dimethylarsenite [dimethyl-As(III)], or Cd(II). (iv) ArsK reduced the cellular accumulation of As(III), Sb(III), Rox(III), and MAs(III) but not to As(V) or dimethyl-As(III). (v) A putative arsenic regulator gene arsR2 was cotranscribed with arsK, and (vi) ArsR2 interacted with the arsR2-arsK promoter region without metalloids and was derepressed by As(III), Sb(III), Rox(III), and MAs(III), indicating the repression activity of ArsR2 for the transcription of arsK These results demonstrate that ArsK is a novel arsenic efflux protein for As(III), Sb(III), Rox(III), and MAs(III) and is regulated by ArsR2. Bacteria use the arsR2-arsK operon for resistance to several trivalent arsenicals or antimonials.IMPORTANCE The metalloid extrusion systems are very important bacterial resistance mechanisms. Each of the previously reported ArsB, Acr3, ArsP, ArsJ, and MSF1 transport proteins conferred only inorganic or organic arsenic/antimony resistance. In contrast, ArsK confers resistance to several inorganic and organic trivalent arsenicals and antimonials. The identification of the novel efflux transporter ArsK enriches our understanding of bacterial resistance to trivalent arsenite [As(III)], antimonite [Sb(III)], trivalent roxarsone [Rox(III)], and methylarsenite [MAs(III)].

Dataset Information

Arsenite oxidase in complex with antimonite and arsenite oxyanions: Insights into the catalytic mechanism.

Publications

Arsenite oxidase in complex with antimonite and arsenite oxyanions: Insights into the catalytic mechanism.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets