Premium
Identification of a copper‐repressible C‐type heme protein of Methylococcus capsulatus (Bath)
Author(s) -
Karlsen Odd A.,
Kindingstad Louise,
Angelskår Solveig M.,
Bruseth Live J.,
Straume Daniel,
Puntervoll Pål,
Fjellbirkeland Anne,
Lillehaug Johan R.,
Jensen Harald B
Publication year - 2005
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2005.05020.x
Subject(s) - heme , biochemistry , biology , peptide sequence , peroxidase , cytochrome , periplasmic space , hemeprotein , escherichia coli , gene , enzyme
Genomic sequencing of the methanotrophic bacterium, Methylococcus capsulatus (Bath), revealed an open reading frame ( MCA2590 ) immediately upstream of the previously described mopE gene (MCA2589). Sequence analyses of the deduced amino acid sequence demonstrated that the MCA2590‐encoded protein shared significant, but restricted, sequence similarity to the bacterial di‐heme cytochrome c peroxidase (BCCP) family of proteins. Two putative C‐type heme‐binding motifs were predicted, and confirmed by positive heme staining. Immunospecific recognition and biotinylation of whole cells combined with MS analyses confirmed expression of MCA2590 in M. capsulatus as a protein noncovalently associated with the cellular surface of the bacterium exposed to the cell exterior. Similar to MopE, expression of MCA2590 is regulated by the bioavailability of copper and is most abundant in M. capsulatus cultures grown under low copper conditions, thus indicating an important physiological role under these growth conditions. MCA2590 is distinguished from previously characterized members of the BCCP family by containing a much longer primary sequence that generates an increased distance between the two heme‐binding motifs in its primary sequence. Furthermore, the surface localization of MCA2590 is in contrast to the periplasmic location of the reported BCCP members. Based on our experimental and bioinformatical analyses, we suggest that MCA2590 is a member of a novel group of bacterial di‐heme cytochrome c peroxidases not previously characterized.