cDNA cloning of a Trichoderma reesei cellulase and demonstration of endoglucanase activity by expression in yeast.
A Trichoderma reesei cDNA encoding a previously unknown protein with a C-terminal cellulose-binding domain was obtained by complementation screening of a T. reesei cDNA library in a sec1 yeast mutant impaired in protein secretion. The T. reesei protein shows amino acid similarity over its entire length to the Agaricus bisporus cellulose-induced protein CEL1 whose function is not known. These two proteins form a new glycosyl hydrolase family, number 61. Expression of the T. reesei cDNA in yeast showed that it encoded a protein with endoglucanase activity and thus the protein was named EGIV and the corresponding gene egl4. Polyclonal antibodies were prepared against EGIV produced in Escherichia coli and detected a 56-kDa protein in the T. reesei culture supernatant. Northern hybridisation revealed that T. reesei egl4 is regulated in the same manner as other cellulase genes of this fungus.
Saloheimo
M
M
VTT Biotechnology and Food Research, Espoo, Finland. markku.saloheimo@vtt.fi
Nakari-Setälä
T
T
Tenkanen
M
M
Penttilä
M
M
D000364:Agaricus / Q000201:enzymology; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002480:Cellulase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D043366:Cellulose 1,4-beta-Cellobiosidase; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005656:Fungal Proteins; D015723:Gene Library; D005800:Genes, Fungal; D008961:Models, Structural; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014242:Trichoderma / Q000201:enzymology* / Q000235:genetics
D018076:DNA, Complementary; D005656:Fungal Proteins; D011994:Recombinant Proteins; D002480:Cellulase; C109208:EGL4 protein, Hypocrea jecorina; D043366:Cellulose 1,4-beta-Cellobiosidase