The copper-linked Escherichia coli AZY operon: Structure, metal binding, and a possible physiological role in copper delivery
| Autor: | Nurit Livnat-Levanon, Nir Ben-Tal, Elena Vigonsky, Amy C. Rosenzweig, Rose C. Hadley, Jessica Rose, Oded Lewinson, Gal Masrati, Daniel Zhitnitsky |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
crystal structure
Operon Protein Data Bank (RCSB PDB) lac operon HMM Hidden Markov model Biochemistry NDH-2 NADH dehydrogenase II chemistry.chemical_compound Structure-Activity Relationship JGI Joint Genome Institute PDB Protein Data Bank Metalloprotein Escherichia coli pfam10709 Protein family 10709 Molecular Biology Chelating Agents chemistry.chemical_classification Escherichia coli Proteins DUF2511 Domain of Unknown Function 2511 metalloprotein Cue Cu efflux TCEP Tris(2-carboxyethyl)phosphine Cell Biology Periplasmic space bioinformatics Cus Cu sensing E. coli ICP–MS inductively coupled plasma MS MSA multiple sequence alignment SEC–MALS size-exclusion chromatography with multiangle light scattering chemistry Membrane protein DOE Department of Energy Periplasmic Binding Proteins copper transport metal homeostasis AZY yobA–yebZ–yebY Cop/Pco copper resistance or plasmid-borne copper resistance Copper Isopropyl β-D-1-thiogalactopyranoside Cysteine Research Article |
| Zdroj: | The Journal of Biological Chemistry |
| ISSN: | 1083-351X 0021-9258 |
| Popis: | The Escherichia coli yobA–yebZ–yebY (AZY) operon encodes the proteins YobA, YebZ, and YebY. YobA and YebZ are homologs of the CopC periplasmic copper-binding protein and the CopD putative copper importer, respectively, whereas YebY belongs to the uncharacterized Domain of Unknown Function 2511 family. Despite numerous studies of E. coli copper homeostasis and the existence of the AZY operon in a range of bacteria, the operon's proteins and their functional roles have not been explored. In this study, we present the first biochemical and functional studies of the AZY proteins. Biochemical characterization and structural modeling indicate that YobA binds a single Cu2+ ion with high affinity. Bioinformatics analysis shows that YebY is widespread and encoded either in AZY operons or in other genetic contexts unrelated to copper homeostasis. We also determined the 1.8 Å resolution crystal structure of E. coli YebY, which closely resembles that of the lantibiotic self-resistance protein MlbQ. Two strictly conserved cysteine residues form a disulfide bond, consistent with the observed periplasmic localization of YebY. Upon treatment with reductants, YebY binds Cu+ and Cu2+ with low affinity, as demonstrated by metal-binding analysis and tryptophan fluorescence. Finally, genetic manipulations show that the AZY operon is not involved in copper tolerance or antioxidant defense. Instead, YebY and YobA are required for the activity of the copper-related NADH dehydrogenase II. These results are consistent with a potential role of the AZY operon in copper delivery to membrane proteins. |
| Databáze: | OpenAIRE |
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