Homology between cellulase genes of Trichoderma reesei: complete nucleotide sequence of the endoglucanase I gene

Merja Penttilä, Päivi Lehtovaara, Helena Nevalainen, Ramagauri Bhikhabhai, Jonathan Knowles

Research output: Contribution to journalArticleScientificpeer-review

250 Citations (Scopus)

Abstract

The filamentous fungus Trichoderma reesei produces several endoglucanases (EG) and cellobiohydrolases (CBH) which are involved in cellulose hydrolysis in a complex synergistic manner. We have cloned and sequenced the gene and the full-length cDNA coding for the major endoglucanase EG-I, and compared this to the cbhl gene sequence to clarify the relationship between the EG and CBH classes of cellulases. The deduced 437-amino acids (aa) long EG-I protein with a 22-aa long signal peptide is 45% identical in aa sequence with CBH-I. The best conserved region is found at the C terminus and shows about 70% homology. The data suggest that the two enzymes have arisen from a common ancestor by gene duplication. Despite this, the intron positions have not been conserved in these genes which both contain two short introns. The deduced EG-I sequence contains six putative N-glycosylation sites, and a putative O-glycosylated region is found near the C terminus, closely resembling a similar region at the C terminus of CBH-I. Comparison of the aa sequences suggests that the evolutionary divergence of EG-I from CBH-I has involved four separate 10-20 aa "deletions" from the ancestral protein.

Original languageEnglish
Pages (from-to)253-263
Number of pages11
JournalGene
Volume45
Issue number3
DOIs
Publication statusPublished - 1 Jan 1986
MoE publication typeA1 Journal article-refereed

Keywords

  • cDNA
  • cellobiohydrolase
  • filamentous fungus
  • gene family
  • glycosylation
  • introns
  • phage λ clones
  • Recombinant DNA

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