L. Le Guen et al., Functional analysis of the hemK gene product involvement in protoporphyrinogen oxidase activity in yeast, FEMS MICROB, 173(1), 1999, pp. 175-182
The Escherichia coil hemK gene has been described as being involved in prot
oporphyrinogen oxidase activity; however, there is no biochemical evidence
for this. In the context of characterizing the mechanisms of protoporphyrin
ogen oxidation in the yeast Saccharomyces cerevisiae, we investigated the y
east homolog of HemK, which is encoded by the ORF YNL063w, to find out whet
her it has any protoporphyrinogen oxidase activity and/or whether it modula
tes protoporphyrinogen oxidase activity. Phenotype analysis and enzyme acti
vity measurements indicated that the yeast HemK homolog is not involved in
protoporphyrinogen oxidase activity. Complementation assays in which the ye
ast HemK homolog is overproduced do not restore wild-type phenotypes in a y
east strain with deficient protoporphyrinogen oxidase activity. Protein seq
uence analysis of HemK-related proteins revealed consensus motif for S-aden
osyl-methionine-dependent methyltransferase. (C) 1999 Federation of Europea
n Microbiological Societies. Published by Elsevier Science B.V. All rights
reserved.