MbnH is a diheme MauG-like protein associated with microbial copper homeostasis.

Autor:	Kenney GE; Departments of Molecular Biosciences and Chemistry, Northwestern University, Evanston, Illinois 60208., Dassama LMK; Departments of Molecular Biosciences and Chemistry, Northwestern University, Evanston, Illinois 60208., Manesis AC; Departments of Molecular Biosciences and Chemistry, Northwestern University, Evanston, Illinois 60208., Ross MO; Departments of Molecular Biosciences and Chemistry, Northwestern University, Evanston, Illinois 60208., Chen S; Departments of Molecular Biosciences and Chemistry, Northwestern University, Evanston, Illinois 60208., Hoffman BM; Departments of Molecular Biosciences and Chemistry, Northwestern University, Evanston, Illinois 60208., Rosenzweig AC; Departments of Molecular Biosciences and Chemistry, Northwestern University, Evanston, Illinois 60208 amyr@northwestern.edu.
Jazyk:	angličtina
Zdroj:	The Journal of biological chemistry [J Biol Chem] 2019 Nov 01; Vol. 294 (44), pp. 16141-16151. Date of Electronic Publication: 2019 Sep 11.
DOI:	10.1074/jbc.RA119.010202
Abstrakt:	Methanobactins (Mbns) are ribosomally-produced, post-translationally modified peptidic copper-binding natural products produced under conditions of copper limitation. Genes encoding Mbn biosynthetic and transport proteins have been identified in a wide variety of bacteria, indicating a broader role for Mbns in bacterial metal homeostasis. Many of the genes in the Mbn operons have been assigned functions, but two genes usually present, mbnP and mbnH , encode uncharacterized proteins predicted to reside in the periplasm. MbnH belongs to the bacterial diheme cytochrome c peroxidase (bCcP)/MauG protein family, and MbnP contains no domains of known function. Here, we performed a detailed bioinformatic analysis of both proteins and have biochemically characterized MbnH from Methylosinus ( Ms. ) trichosporium OB3b. We note that the mbnH and mbnP genes typically co-occur and are located proximal to genes associated with microbial copper homeostasis. Our bioinformatics analysis also revealed that the bCcP/MauG family is significantly more diverse than originally appreciated, and that MbnH is most closely related to the MauG subfamily. A 2.6 Å resolution structure of Ms. trichosporium OB3b MbnH combined with spectroscopic data and peroxidase activity assays provided evidence that MbnH indeed more closely resembles MauG than bCcPs, although its redox properties are significantly different from those of MauG. The overall similarity of MbnH to MauG suggests that MbnH could post-translationally modify a macromolecule, such as internalized CuMbn or its uncharacterized partner protein, MbnP. Our results indicate that MbnH is a MauG-like diheme protein that is likely involved in microbial copper homeostasis and represents a new family within the bCcP/MauG superfamily. (© 2019 Kenney et al.)
Databáze:	MEDLINE
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