Expression of glr (murI, dga) gene encoding glutamate racemase in Escherichia coli.
The murI (dga) gene of Escherichia coli is required for the biosynthesis of D-glutamate, an essential component of bacterial peptidoglycan (Doublet, P., van Heijetnoort, J., and Mengin-Lecreulx, D. (1992) J. Bacteriol. 174, 5772-5779; Dougherty, T. J., Thanassi, J. A., and Pucci, M. J. (1993) J. Bacteriol. 175, 111-116), but its gene product has not been identified. We found that the amino acid sequence of protein deduced from the nucleotide sequence of the open reading frame of murI gene (ORF1) shows a significant homology with that of glutamate racemase of Pediococcus pentosaceus. The amino acid sequence of glutamate racemase of Lactobacillus fermenti recently reported also shows a homology with the deduced amino acid sequence of ORFI (Gallo, K. A., and Knowles, J. R. (1993) Biochemistry 32, 3981-3990). The murI (dga) gene was ligated into a plasmid, pKK223-3, with a designed ribosome binding site and expressed in E. coli JM109 cells. Glutamate racemase was produced by the transformant cells, whereas the enzyme was not found in the host cells. Accordingly, we newly termed the gene glr, which is more relevant than murI and dga. We partially purified the enzyme to characterize it. The enzyme consists of two identical subunits with a molecular weight of about 31,000 in contrast to the P. pentosaceus enzyme, a monomer protein.
Yoshimura
T
T
Institute for Chemical Research, Kyoto University, Japan.
Ashiuchi
M
M
Esaki
N
N
Kobatake
C
C
Choi
S Y
SY
Soda
K
K
D000591:Amino Acid Isomerases / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D015870:Gene Expression; D005971:Glutamates / Q000378:metabolism; D018698:Glutamic Acid; D007656:Ketoglutaric Acids / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010457:Peptidoglycan / Q000378:metabolism; D011392:Proline / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D005971:Glutamates; D007656:Ketoglutaric Acids; D010457:Peptidoglycan; D018698:Glutamic Acid; D011392:Proline; D000591:Amino Acid Isomerases; C062292:glutamate racemase