Purification and molecular cloning of xylanases from the wood-feeding termite, Coptotermes formosanus Shiraki.
Coptotermes formosanus is one of the most destructive termites in the southern part of Japan as well as in the United States. Hemicellulose is a noncellulosic polysaccharide found in plant cell walls, and xylan is the major constituent of hemicellulose. Since hemicellulose prevents access of cellulolytic enzymes to cellulose, enzymatic hydrolysis of hemicellulose is beneficial for cellulose digestion. We purified three functional xylanases to homogeneity from C. formosanus for the first time. Elution profiles from the whole termite extract suggest that these three xylanases play major roles in xylan digestion in the gut of the termites. The corresponding cDNAs were successfully cloned based on the N-terminal amino acid sequences, encoding GHF11 xylanases. Reverse transcription-PCR using manipulated protozoan cells in the hindgut revealed that the corresponding genes were expressed in the symbiotic flagellate Holomastigotoides mirabile. These results suggest that the GHF11 xylanases that are produced by the symbiotic flagellates play a primary role in xylan degradation in C. formosanus.
Arakawa
Gaku
G
Center of Molecular Biosciences (COMB), University of the Ryukyus, Nishihara, Okinawa, Japan.
Watanabe
Hirofumi
H
Yamasaki
Hideo
H
Maekawa
Hideaki
H
Tokuda
Gaku
G
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002845:Chromatography; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D041981:Gastrointestinal Tract / Q000201:enzymology; D020049:Isoptera / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D021141:Nucleic Acid Amplification Techniques; D013559:Symbiosis; D014995:Xylosidases / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism
D018076:DNA, Complementary; D014995:Xylosidases