The CaCel gene from Antarctic springtail Cryptopygus antarcticus codes for a cellulase belonging to the glycosyl hydrolase family 45 (GHF45). Phylogenetic, biochemical, and structural analyses revealed that the CaCel gene product (CaCel) is closely related to fungal GHF45 endo-β-1,4-glucanases. The organization of five introns within the open reading frame of the CaCel gene indicates its endogenous origin in the genome of the species, which suggests the horizontal transfer of the gene from fungi to the springtail. CaCel exhibited optimal activity at pH 3.5, retained 80% of its activity at 0-10 °C, and maintained a half-life of 4 h at 70 °C. Based on the structural comparison between CaCel and a fungal homologue, we deduced the structural basis for the unusual characteristics of CaCel. Under acidic conditions at 50 °C, CaCel was effective to digest the green algae (Ulva pertusa), suggesting that it could be exploited for biofuel production from seaweeds.
Bibliographical noteFunding Information:
This study was supported by the KIOST in-house programs (PE99413, PE98933, and PO00110) the National Research Foundation of Korea Grants (NRF-2015R1A2A2A01004168 and NRF-2015M1A5A1037480), and a grant from the Marine Biotechnology Program (PJT200620) funded by the Ministry of Oceans and Fisheries Korea.
- Cryptopygus antarcticus
- biochemical and structural features
- biofuel production from seaweeds
- cold-active cellulase
- horizontal gene transfer