Sequence of a cellulase gene from the rumen anaerobe Ruminococcus flavefaciens 17

A cellulase gene (endA) was isolated from a library of Ruminococcus flavefaciens strain 17 DNA fragments inserted in pUC13. The endA product showed activity against acid-swollen cellulose, carboxymethyl-cellulose, lichenan, cellopentaose and cellotetraose, but showed no activity against cellotriose or binding to avicel. Nucleotide sequencing indicated an encoded product of 455 amino acids which showed significant sequence similarity (ranging from 56% to 61%) with three endoglucanases from Ruminococcus albus, and with Clostridium thermocellum endoglucanase E. Little relatedness was found with a cellodextrinase previously isolated from R. flavefaciens FD1.