Hybrid bacillus endo-(1-3,1-4)-beta-glucanases: construction of recombinant genes and molecular properties of the gene products.
Hybrid beta-glucanase genes were constructed by the reciprocal exchange of the two halves of the isolated beta-glucanase genes from Bacillus amyloliquefaciens and B. macerans. The beta-glucanase hybrid enzyme 1 (H1) contains the 107 amino-terminal residues of mature B. amyloliquefaciens beta-glucanase and the 107 carboxyl-terminal amino acid residues of B. macerans beta-glucanase. The reciprocal beta-glucanase hybrid enzyme 2 (H2) consists of the 105 amino-terminal residues from the B. macerans enzyme and the carboxyl-terminal 107 amino acids from B. amyloliquefaciens. The biochemical properties of the two hybrid enzymes differ significantly from each other as well as from both parental beta-glucanases. Hybrid beta-glucanase H1 exhibits increased thermostability in comparison to other beta-glucanases, especially in an acidic environment. This hybrid enzyme has maximum activity between pH 5.6 and 6.6, whereas the pH-optimum for enzymatic activity of B. amyloliquefaciens beta-glucanase was found to be at pH 6 to 7 and for B. macerans at pH 6.0 to 7.5. Hybrid enzyme 1 being more heat stable than both parental enzymes represents a case of intragenic heterosis. Hybrid beta-glucanase 2 (H2) was found to be more thermolabile than the naturally occurring beta-glucanases it was derived from and the pH-optimum for enzymatic activity was determined to be between pH 7 and pH 8.
Borriss
R
R
Sektion Nahrungsgüterwirtschaft und Lebensmitteltechnologie, Bereich Mikrobiologie, Humboldt-Universität Berlin, DDR.
Olsen
O
O
Thomsen
K K
KK
von Wettstein
D
D
D000595:Amino Acid Sequence; D001407:Bacillus / Q000201:enzymology / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005796:Genes; D005798:Genes, Bacterial; D005822:Genetic Vectors; D006026:Glycoside Hydrolases / Q000235:genetics* / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D010957:Plasmids; D011994:Recombinant Proteins / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D011994:Recombinant Proteins; D006026:Glycoside Hydrolases; C028020:licheninase