Effect of cysteine desulfhydrase gene disruption on L-cysteine overproduction in Escherichia coli.
In Escherichia coli, the enzyme called cysteine desulfhydrase (CD), which is responsible for L-cysteine degradation, was investigated by native-PAGE and CD activity staining of crude cell extracts. Analyses with gene-disrupted mutants showed that CD activity resulted from two enzymes: tryptophanase (TNase) encoded by tnaA and cystathionine beta-lyase (CBL) encoded by metC. It was also found that TNase synthesis was induced by the presence of L-cysteine. The tnaA and metC mutants transformed with the plasmid containing the gene for feedback-insensitive serine acetyltransferase exhibited higher L-cysteine productivity than the wild-type strain carrying the same plasmid. These results indicated that TNase and CBL did act on L-cysteine degradation in E. coli cells.
Awano
N
N
Department of Bioscience, Fukui Prefectural University, 4-1-1 Kenjyojima, Matsuoka-cho, 910-1195, Fukui, Japan.
Wada
M
M
Kohdoh
A
A
Oikawa
T
T
Takagi
H
H
Nakamori
S
S
D001483:Base Sequence; D003542:Cystathionine gamma-Lyase / Q000235:genetics* / Q000378:metabolism; D003545:Cysteine / Q000096:biosynthesis*; D004269:DNA, Bacterial / Q000235:genetics; D004790:Enzyme Induction; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D018390:Gene Targeting; D005798:Genes, Bacterial; D008190:Lyases / Q000096:biosynthesis / Q000235:genetics; D016254:Mutagenesis, Insertional; D014368:Tryptophanase / Q000096:biosynthesis / Q000235:genetics
D004269:DNA, Bacterial; D008190:Lyases; D014368:Tryptophanase; D003542:Cystathionine gamma-Lyase; C019965:cystathionine beta-lyase; D003545:Cysteine