Structural and Functional Investigation of the Periplasmic Arsenate-Binding Protein ArrX from Chrysiogenes arsenatis
| Autor: | Nilakhi Poddar, Shadi Maghool, Consuelo Badilla, Megan J. Maher, Thomas H. Osborne, Joanne M. Santini |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
0303 health sciences
biology Stereochemistry 030302 biochemistry & molecular biology Chrysiogenes arsenatis Arsenate Periplasmic space biology.organism_classification Ligand (biochemistry) Biochemistry 03 medical and health sciences chemistry.chemical_compound Arsenate reductase chemistry Periplasmic Binding Proteins Binding site Arsenite |
| Zdroj: | Biochemistry. 60:465-476 |
| ISSN: | 1520-4995 0006-2960 |
| Popis: | The anaerobic bacterium Chrysiogenes arsenatis respires using the oxyanion arsenate (AsO43-) as the terminal electron acceptor, where it is reduced to arsenite (AsO33-) 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 Rhizobium 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. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|