Cloning and Expression of β-glucanase Gene from Clostridium. sp

A gene encoding a 鄄glucanase from Clostridium.sp has been cloned and expressed in Escherichia coli, The whole length of the gene is 1040 bp, containing an open reading frame (ORF) of 1003 bp, which encodes 334 amino acids. The enzyme shows a molecular weight of 37.8 kD and a pl of 7.67. The nucleotide sequence of the gene shares high homology to that of Clostridium thermocellum accessed in GeneBank, and the similarity is 99%. The gene has been registered in GeneBank (Accession number is AY225218). The gene from recombinant cloning plasmid was subcloned into BamH Ⅰand Xho Ⅰsite of expression plasmid pET-col in E. coli The recombinant expression plasmid was transformed into E.coli strain BL21. The result of SDS-PAGE showed that about 37 kD protein of the 鄄1,3-1,4-glucanase was expressed in E.coli strain BL21. The enzyme activity of E. coli expressed strain was 29.4 U/mL, which was about 15-fold higher than that of original strain. The pH and temperature at which the highest activity was found were 9 and 80℃ respectively. It's good material for gene engineer to construct highly active and thermophilic enzymatic strain.