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Functional analysis of structural genes for NAD + ‐dependent formate dehydrogenase in Saccharomyces cerevisiae
Author(s) -
Overkamp Karin M.,
Kötter Peter,
van der Hoek Richard,
SchoondermarkStolk Sung,
Luttik Marijke A. H.,
van Dijken Johannes P.,
Pronk Jack T.
Publication year - 2002
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.856
Subject(s) - formate dehydrogenase , formate , biochemistry , biology , orfs , mutant , dehydrogenase , saccharomyces cerevisiae , structural gene , chemostat , gene , enzyme , open reading frame , peptide sequence , genetics , bacteria , catalysis
Co‐consumption of formate by aerobic, glucose‐limited chemostat cultures of Saccharomyces cerevisiae CEN.PK 113‐7D led to an increased biomass yield relative to cultures grown on glucose as the sole carbon and energy substrate. In this respect, this strain differed from two previously investigated S. cerevisiae strains, in which formate oxidation did not lead to an increased biomass yield on glucose. Enzyme assays confirmed the presence of a formate‐inducible, cytosolic and NAD + ‐dependent formate dehydrogenase. To investigate whether this enzyme activity was entirely encoded by the previously reported FDH1 gene, an fdh1Δ null mutant was constructed. This mutant strain still contained formate dehydrogenase activity and remained capable of co‐consumption of formate. The formate dehydrogenase activity in the mutant was demonstrated to be encoded by a second structural gene for formate dehydrogenase ( FDH2 ) in S. cerevisiae CEN.PK 113‐7D. FDH2 was highly homologous to FDH1 and consisted of a fusion of two open reading frames (ORFs) ( YPL275w and YPL276w ) reported in the S. cerevisiae genome databases. Sequence analysis confirmed that, in the database genetic background, the presence of two single‐nucleotide differences led to two truncated ORFs rather than the full‐length FDH2 gene present in strain CEN.PK 113‐7D. In the latter strain background an fdh1Δfdh2Δ double mutant lacked formate dehydrogenase activity and was unable to co‐consume formate. Absence of formate dehydrogenase activity did not affect growth on glucose as sole carbon source, but led to a reduced biomass yield on glucose–formate mixtures. These findings are consistent with a role of formate dehydrogenase in the detoxification of exogenous formate. Copyright © 2002 John Wiley & Sons, Ltd.