CLONING AND SEQUENCING OF AN ENDO-BETA-1,4-GLUCANASE GENE MCENA FROM MICROMONOSPORA-CELLULOLYTICUM 86W-16

Endo-beta-1,4-glucanase gene mcenA of Micromonospora cellulolyticum 86 W-16 was cloned, and the nucleotide sequence was determined. An open r eading frame (ORF) of 1374 bases, coding for a peptide (McenA) of 457 amino acids and 46742 Da, was found. It is preceded by a Gram-positive type of ribosomebinding site and followed by an imperfect inverted re peat. A putative signal peptide containing 23 amino acids is at the N- terminus and a linker region possessing 37 amino acids is in the midpa rt of McenA. The N-half of McenA functions as the catalytic domain and the C-half might serve as a cellulose-binding domain (CBD). Deletion of the latter did not decrease the CMCase activity of McenA. Significa nt similarity (70%) was found between the amino acid sequences of Mcen A and MbcelA, an endoglucanase from Microbispora bispora.