Cloning and characterization of the glycogen branching enzyme gene existing in tandem with the glycogen debranching enzyme from Pectobacterium chrysanthemi PY35

The glycogen branching enzyme gene (g/gB) from Pectobacterium chrysanthemi PY35 was cloned, sequenced, and expressed in Eschcrichia coli, The g/gB gene consisted of an open reading frame of 2196 bp encoding a protein of 731 amino acids (calculated molecular weight of 83.859 Da). The g/gB gene is upstream of glgX and the ORF starts the ATG initiation codon and ends with the TGA stop codon at 2 bp upstream of glgX. The enzyme was 43-69%, sequence identical with other glycogen branching enzymes. The enzyme is the most similar to GlgB of E coli and contained the four regions conserved among the a-amylase family. The glycogen branching enzyme (GlgB) was purified and the molecular weight of the enzyme was estimated to be 84 kDa by SDS-PAGE. The glycogen branching enzyme was optimally active at pH 7 and 30 degreesC. (C) 2002 Elsevier Science (USA). All rights reserved.