Cellulase genes from the parabasalian symbiont <Emphasis Type="Italic">Pseudotrichonympha grassii</Emphasis> in the hindgut of the wood-feeding termite <Emphasis Type="Italic">Coptotermes formosanus</Emphasis> |
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Authors: | K Nakashima H Watanabe J-I Azuma |
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Institution: | (1) Division of Environmental Science and Technology, Graduate School of Agriculture, Kyoto University, Sakyo-Ku, Kyoto 606-8502 (Japan), JP;(2) National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8634 (Japan), Fax: + 81 298 38 6108, e-mail: hinabe@affrc.go.jp, JP |
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Abstract: | 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.
Received 10 July 2002; accepted 26 July 2002
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ID="*"Corresponding author. |
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Keywords: | , Cellulase, Pseudotrichonympha grassii, parabasalia, symbiosis, termite, Coptotermes formosanus, glycoside hydrolase,,,,,family 7, |
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