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The presence of multiple c ‐type cytochromes at the surface of the methanotrophic bacterium Methylococcus capsulatus (Bath) is regulated by copper
Author(s) -
Karlsen O. A.,
Lillehaug J. R.,
Jensen H. B.
Publication year - 2008
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2008.06380.x
Subject(s) - biology , bacteria , copper , microbiology and biotechnology , type (biology) , ecology , genetics , metallurgy , materials science
Summary Identification of surface proteins is essential to understand bacterial communication with its environment. Analysis of the surface‐associated proteins of Methylococcus capsulatus (Bath) revealed a highly dynamic structure responding closely to the availability of copper in the medium in the range from ∼0 to 10 μM. Several c ‐type cytochromes, including three novel multihaem proteins, are present at the cellular surface, a feature that is otherwise a peculiarity of dissimilatory metal‐reducing bacteria. At low copper concentrations, the cytochrome c 553o and the cytochrome c 553o family protein, encoded by the MCA0421 and MCA0423 genes, respectively, are major constituents of the surfaceome and show a fine‐tuned copper‐dependent regulation of expression. Two novel members of the cytochrome c 553o family were identified: MCA0338 was abundant between 5 and 10 μM copper, while MCA2259 was detected only in the surface fraction obtained from ∼0 μM copper cultures. The presence at the bacterial surface of several c ‐type cytochromes, generally involved in energy transduction, indicates strongly that redox processes take place at the bacterial surface. Due to the unique role of copper in the biology of M. capsulatus (Bath), it appears that c ‐type cytochromes have essential functions in copper homeostasis allowing the cells to adapt to varying copper exposure.