Study on the production and species-specificity of methanobactin

Methanobactin is a small peptide that appears to function as an agent for copper sequestration and uptake in methanotrophs. It isn’t known whether the ability to produce methanobactin is wide-spread in methanotrophs and whether the methanobactin characteristics are identical or they vary with strain. In this work, methanobactin production was determined by split mineral salts/Cu–CAS plates. The effect of copper concentration on the methanobactin production was investigated. To examine the species-specificity of methanobactin, four kinds of methanotrophic cells grown in copper-free mineral salts medium were washed and resuspended in high copper concentrations medium with or without Methylosinus trichosporium 3011 Mb addition. Methanobactin from Methylosinus trichosporium 3011 can shorten the copper-shock lag phase of all tested methanotrophs upon sudden exposure to elevated copper concentration and can stimulate Methane Monooxygenase activity of all tested methanotrophs in the presence of copper. The results suggested that the production of methanobactin may be a widespread characteristic of methanotrophs and methanotrophs may take delivery of copper from methanobactin released by other species. This result would be beneficial to insight into the diversity of methanobactin structure and what role it may play in interspecies competition or cooperation for copper ion.