ISOLATION OF A BETA-GALACTOSIDASE-ENCODING GENE FROM BACILLUS-LICHENIFORMIS - PURIFICATION AND CHARACTERIZATION OF THE RECOMBINANT ENZYME EXPRESSED IN ESCHERICHIA-COLI
Lsp. Tran et al., ISOLATION OF A BETA-GALACTOSIDASE-ENCODING GENE FROM BACILLUS-LICHENIFORMIS - PURIFICATION AND CHARACTERIZATION OF THE RECOMBINANT ENZYME EXPRESSED IN ESCHERICHIA-COLI, Current microbiology, 37(1), 1998, pp. 39-43
The Bacillus licheniformis beta-galactosidase gene, lacBl, was cloned
on a 5.8-kb HindIII fragment into pBR322 and expressed by its own prom
oter in Escherichia coli. Deletion and complementation analysis showed
that the enzyme-encoding region was located on a 4.1-kb HindIII-ClaI
fragment. The transcription region for the lacBl was identified on thi
s fragment with promoter-and terminator-probe plasmids. The deduced se
quence of 149 aa of the N-terminal part of lacBl showed aa sequence ho
mology with beta-Gal from B, stearothermophilus, B. circulans, Halofer
ax alicantei, Clostridium perfringens, Arthrobacter sp., No significan
t homology was shared with those found in the lacZ and lacS families.
The recombinant beta-galactosidase (LacB1) was purified by FPLC. The m
olecular mass of the enzyme (80 kDa) and its optimal pH (5.7) and temp
erature (45 degrees C) were determined.