
Investigation of direct vs. indirect involvement of the c ‐type cytochrome MacA in Fe(III) reduction by Geobacter sulfurreducens
Author(s) -
Kim ByoungChan,
Lovley Derek R.
Publication year - 2008
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2008.01252.x
Subject(s) - geobacter sulfurreducens , cytochrome , electron transfer , cytochrome c , chemistry , mutant , geobacter , electron transport chain , bacterial outer membrane , wild type , biophysics , biochemistry , biology , gene , enzyme , bacteria , genetics , mitochondrion , escherichia coli , photochemistry , biofilm
The electron transfer pathway to Fe(III) reduction in Geobacter sulfurreducens has been hypothesized to consist of a series of c ‐type cytochromes. Previous genetic studies suggested that the inner membrane‐associated, c ‐type cytochrome, MacA, was a component of the electron transfer chain leading to Fe(III) reduction in the dissimilatory Fe(III)‐reducer, G. sulfurreducens . However, investigation of the expression of OmcB, an outer‐membrane c ‐type cytochrome demonstrated previously to be critical for optimal Fe(III) reduction, revealed that both omcB transcript and protein levels were dramatically reduced in the MacA‐deficient mutant. Expression of the omcB gene in trans enabled the MacA‐deficient mutant to reduce Fe(III) at a rate that was proportional to the level of omcB expression. These results suggest that MacA is not directly involved in electron transfer to Fe(III) and further confirm the importance of OmcB in Fe(III) reduction by G. sulfurreducens .