6XAD

Structure of the formate-bound form of ArrX from Chrysiogenes arsenatis

Summary for 6XAD

• Entry DOI: 10.2210/pdb6xad/pdb
• Descriptor: ArrX, FORMIC ACID (3 entities in total)
• Functional Keywords: periplasmic binding protein, signaling protein
• Biological source: Chrysiogenes arsenatis
• Total number of polymer chains: 1
• Total formula weight: 34384.83

Authors

Maher, M.J.,Poddar, N. (deposition date: 2020-06-04, release date: 2021-02-17, Last modification date: 2023-10-18)

Primary citation

Poddar, N.,Badilla, C.,Maghool, S.,Osborne, T.H.,Santini, J.M.,Maher, M.J.
Structural and Functional Investigation of the Periplasmic Arsenate-Binding Protein ArrX from Chrysiogenes arsenatis .
Biochemistry, 60:465-476, 2021

PubMed Abstract: The anaerobic bacterium respires using the oxyanion arsenate (AsO) as the terminal electron acceptor, where it is reduced to arsenite (AsO) while concomitantly oxidizing various organic (e.g., acetate) electron donors. This respiratory activity is catalyzed in the periplasm of the bacterium by the enzyme arsenate reductase (Arr), with expression of the enzyme controlled by a sensor histidine kinase (ArrS) and a periplasmic-binding protein (PBP), ArrX. Here, we report for the first time, the molecular structure of ArrX in the absence and presence of bound ligand arsenate. Comparison of the ligand-bound structure of ArrX with other PBPs shows a high level of conservation of critical residues for ligand binding by these proteins; however, this suite of PBPs shows different structural alterations upon ligand binding. For ArrX and its homologue AioX (from sp. str. NT-26), which specifically binds arsenite, the structures of the substrate-binding sites in the vicinity of a conserved and critical cysteine residue contribute to the discrimination of binding for these chemically similar ligands.

PubMed: 33538578
DOI: 10.1021/acs.biochem.0c00555

Experimental method

X-RAY DIFFRACTION (1.893 Å)