It has been shown [1] that the following glycosyl hydrolases can be classified into a single family on the basis of sequence similarities:

• Bacterial β-1,3-1,4-glucanases, or lichenases, (EC 3.2.1.73) mainly from Bacillus but also from Clostridium thermocellum (gene licB), Fibrobacter succinogenes and Rhodothermus marinus (gene bglA).
• Bacillus circulans β-1,3-glucanase A1 (EC 3.2.1.39) (gene glcA).
• Streptomyces coelicolor agarase (EC 3.2.1.81) (gene dagA).
• Alteromonas carrageenovora kappa-carrageenase (EC 3.2.1.83) (gene cgkA).
• Rhizobium meliloti endo-1,3-1,4-β-glycanase exoK.

Two closely clustered conserved glutamates have been shown [2] to be involved in the catalytic activity of Bacillus licheniformis lichenase. We used the region that contains these residues as a signature pattern.