Evidence that the Piromyces gene family encoding endo-1,4-mannanases arose through gene duplication.

The sequences of two Piromyces cDNAs (manB and manC) encoding functional mannanases, defined as mannanase B (MANB) and mannanase C (MANC), revealed that both the cDNAs, and the encoded enzymes, exhibited extensive sequence identity with each other and with a previously described Piromyces mannanase. MANB and MANC, which belong to glycosyl hydrolase family 26, hydrolyse several forms of mannan but do not attack the other major plant structural polysaccharides. The data presented in this paper indicate that the Piromyces gene family encoding mannanases arose through gene duplication.