Open AccessIdentification of the cellulose‐binding and the cell wall‐binding domains of Eubacterium cellulosolvens 5 cellulose‐binding protein A (CBPA)
Author(s) -
Toyoda Atsushi,
Minato Hajime
Publication year - 2002
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2002.tb11333.x
Subject(s) - cellulase , cell wall , biochemistry , binding site , binding domain , binding protein , recombinant dna , eubacterium , cellulose , biology , escherichia coli , chemistry , gene , bacteria , genetics
The cellulose‐binding domain (CBD) and the cell wall‐binding domain (CWBD) of Eubacterium cellulosolvens 5 cellulose‐binding protein A (CBPA) have been determined. The gene ( cbpA ) encoding CBPA and its derivatives were expressed in Escherichia coli . We were able to obtain the eight recombinant proteins and examine for their cellulose‐binding ability, cell wall‐binding ability and carboxymethyl cellulase (CMCase) activity. Since five recombinant proteins, which contain the unknown domain (UD‐2) located between two linker‐like regions of CBPA, bound to cellulose, this region has been identified as the CBD. The CBD did not show a significant sequence similarity with any other CBDs. Moreover, the N‐terminal region of CBPA showed a significant sequence similarity with a catalytic domain of glycosyl hydrolase family 9, and the recombinant proteins containing the region showed CMCase activity. Since the UD‐3, which is located in the C‐terminal region of CBPA, bound to the cell walls of E. cellulosolvens 5, the region has been identified as the CWBD. However, the CWBD did not show a significant sequence similarity with any other proteins previously reported.