The bglX gene located at 47.8 min on the Escherichia coli chromosome encodes a periplasmic beta-glucosidase.
A new Escherichia coli gene, bgIX, encoding a beta-D-glucosidase (EC 3.2.1.21) has been characterized. The bgIX gene is located adjacent to the dld gene at 47.8 min or 2225 kb on the E. coli chromosome. The sequence of a 2.6 kb DNA fragment from this region revealed a large open reading frame encoding a protein of 765 amino acids. The BgIX protein was purified from the periplasm, and amino-terminal sequencing suggests that the mature protein is derived from cleavage of a 20 residue signal peptide. A search of the sequence databases revealed that BgIX is a member of a large family of beta-glucosidases from a variety of bacteria and fungi, and the plant Arabidopsis thaliana. It differs from the other four E. coli phospho-beta-glucosidases in sequence and in its periplasmic rather than cytoplasmic location. The BgIX enzyme has a Km of 18 +/- 1 mM and a Vmax of 3 +/- 0.7 mumol min-1 for the colorimetric substrate o-nitrophenyl beta-D-glucopyranoside.
Yang
M
M
Department of Molecular Biology, Genentech Inc., South San Francisco, CA 94080-4990, USA.
Luoh
S M
SM
Goddard
A
A
Reilly
D
D
Henzel
W
W
Bass
S
S
D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial / Q000235:genetics*; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics*; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D010641:Phenotype; D017386:Sequence Homology, Amino Acid; D001617:beta-Glucosidase / Q000235:genetics*
D017931:DNA Primers; D004269:DNA, Bacterial; D001617:beta-Glucosidase