2YGJ

Methanobactin MB4

Summary for 2YGJ

• Entry DOI: 10.2210/pdb2ygj/pdb
• Descriptor: METHANOBACTIN MB4, COPPER (II) ION, SODIUM ION, ... (4 entities in total)
• Functional Keywords: metal transport, methanotrophs
• Biological source: METHYLOCYSTIS SP.
• Total number of polymer chains: 1
• Total formula weight: 1021.53

Authors

Ghazouani, A.,Basle, A.,Firbank, S.J.,Gray, J.,Dennison, C. (deposition date: 2011-04-18, release date: 2012-04-25, Last modification date: 2024-11-13)

Primary citation

El Ghazouani, A.,Basle, A.,Gray, J.,Graham, D.W.,Firbank, S.J.,Dennison, C.
Variations in Methanobactin Structure Influences Copper Utilization by Methane-Oxidizing Bacteria.
Proc.Natl.Acad.Sci.USA, 109:8400-, 2012

PubMed Abstract: Methane-oxidizing bacteria are nature's primary biological mechanism for suppressing atmospheric levels of the second-most important greenhouse gas via methane monooxygenases (MMOs). The copper-containing particulate enzyme is the most widespread and efficient MMO. Under low-copper conditions methane-oxidizing bacteria secrete the small copper-binding peptide methanobactin (mbtin) to acquire copper, but how variations in the structures of mbtins influence copper metabolism and species selection are unknown. Methanobactins have been isolated from Methylocystis strains M and hirsuta CSC1, organisms that can switch to using an iron-containing soluble MMO when copper is limiting, and the nonswitchover Methylocystis rosea. These mbtins are shorter, and have different amino acid compositions, than the characterized mbtin from Methylosinus trichosporium OB3b. A coordinating pyrazinedione ring in the Methylocystis mbtins has little influence on the Cu(I) site structure. The Methylocystis mbtins have a sulfate group that helps stabilize the Cu(I) forms, resulting in affinities of approximately 10(21) M(-1). The Cu(II) affinities vary over three orders of magnitude with reduction potentials covering approximately 250 mV, which may dictate the mechanism of intracellular copper release. Copper uptake and the switchover from using the iron-containing soluble MMO to the copper-containing particulate enzyme is faster when mediated by the native mbtin, suggesting that the amino acid sequence is important for the interaction of mbtins with receptors. The differences in structures and properties of mbtins, and their influence on copper utilization by methane-oxidizing bacteria, have important implications for the ecology and global function of these environmentally vital organisms.

PubMed: 22582172
DOI: 10.1073/PNAS.1112921109

Experimental method

X-RAY DIFFRACTION (0.8 Å)