7L6G

MbnP from Methylosinus trichosporium

Summary for 7L6G

• Entry DOI: 10.2210/pdb7l6g/pdb
• Descriptor: Metallo-mystery pair system four-Cys motif protein, COPPER (II) ION, CALCIUM ION, ... (6 entities in total)
• Functional Keywords: copper, kynurenine, mbnp, metal binding protein
• Biological source: Methylosinus trichosporium OB3b
• Total number of polymer chains: 6
• Total formula weight: 189961.01

Authors

Manesis, A.C.,Rosenzweig, A.C. (deposition date: 2020-12-23, release date: 2021-05-26, Last modification date: 2024-10-30)

Primary citation

Manesis, A.C.,Jodts, R.J.,Hoffman, B.M.,Rosenzweig, A.C.
Copper binding by a unique family of metalloproteins is dependent on kynurenine formation.
Proc.Natl.Acad.Sci.USA, 118:-, 2021

PubMed Abstract: Some methane-oxidizing bacteria use the ribosomally synthesized, posttranslationally modified natural product methanobactin (Mbn) to acquire copper for their primary metabolic enzyme, particulate methane monooxygenase. The operons encoding the machinery to biosynthesize and transport Mbns typically include genes for two proteins, MbnH and MbnP, which are also found as a pair in other genomic contexts related to copper homeostasis. While the MbnH protein, a member of the bacterial diheme cytochrome peroxidase (bCP)/MauG superfamily, has been characterized, the structure and function of MbnP, the relationship between the two proteins, and their role in copper homeostasis remain unclear. Biochemical characterization of MbnP from the methanotroph OB3b now reveals that MbnP binds a single copper ion, present in the +1 oxidation state, with high affinity. Copper binding to MbnP in vivo is dependent on oxidation of the first tryptophan in a conserved WxW motif to a kynurenine, a transformation that occurs through an interaction of MbnH with MbnP. The 2.04-Å-resolution crystal structure of MbnP reveals a unique fold and an unusual copper-binding site involving a histidine, a methionine, a solvent ligand, and the kynurenine. Although the kynurenine residue may not serve as a Cu primary-sphere ligand, being positioned ∼2.9 Å away from the Cu ion, its presence is required for copper binding. Genomic neighborhood analysis indicates that MbnP proteins, and by extension kynurenine-containing copper sites, are widespread and may play diverse roles in microbial copper homeostasis.

PubMed: 34074779
DOI: 10.1073/pnas.2100680118

Experimental method

X-RAY DIFFRACTION (2.04 Å)