Abstract
The gluA gene, encoding an endo-β-1,3-glucanase from Arthrobacter sp. (strain NHB-10), was cloned and analyzed. The deduced endo-β-1,3-glucanase amino acid sequence was 750 amino acids long and contained a 42 amino acid signal peptide with a mature protein of 708 amino acids. There was no similarity to known endo-β-1,3-glucanases, but GluA was partially similar to two fungal exo-β-1,3-glucanases in glycoside hydrolase (GH) family 55. Of five possible residues for catalysis and two motifs in two β-helix heads of GH family 55, three residues and one motif were conserved in GluA, suggesting that GluA is the first bacterial endo-β-1,3-glucanase in GH family 55. Significant similarity was also found to two proteins of unknown function from Streptomyces coelicolor A3(2) and S. avermitilis.
