Cellulase genes from the parabasalian symbiont Pseudotrichonympha grassii in the hindgut of the wood-feeding termite Coptotermes formosanus.
Cellulase genes of Pseudotrichonympha grassii (Hypermastigida: Eucomonymphidae), the symbiotic flagellate in the hindgut of the wood-feeding termite Coptotermes formosanus, were isolated and characterized. The nucleotide sequences of the major cellulase component in the hindgut of C. formosanus were determined based on its N-terminal amino acid sequence. The five isolated nucleotide sequences (PgCBH-homos) had an open reading frame of 1350 bp showing similarity to catalytic domains of glycoside hydrolase family (GHF) 7 members, and primary structure comparison with GHF7 members whose tertiary structures are well-characterized revealed the overall similarity between PgCBH-homo and the catalytic domain of a processive cellulase Cel7A (formerly CBHI) from the aerobic fungus Trichoderma reesei. Functional expression of PgCBH-homos in Escherichia coli, using the carboxymethylcellulose-Congo red assay, demonstrated the actual cellulolytic activity of PgCBH-homo. RT-PCR showed that PgCBH-homos were expressed, from the three flagellates in the hindgut, specifically in P. grassii.
Nakashima
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KI
Watanabe
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H
Azuma
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JI
D000595:Amino Acid Sequence; D000818:Animals; D002480:Cellulase / Q000737:chemistry / Q000145:classification / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D056890:Eukaryota / Q000201:enzymology / Q000235:genetics* / Q000502:physiology; D017125:Genes, Protozoan; D020049:Isoptera / Q000469:parasitology*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D016415:Sequence Alignment; D013559:Symbiosis
D002480:Cellulase