Molecular and biochemical characterizations of a novel arthropod endo-beta-1,3-glucanase from the Antarctic springtail, Cryptopygus antarcticus , horizontally acquired from bacteria

• Published in: Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology
• Main Authors: Song, Jung Min, Nam, Ki Woong, Sun, Young-Uk, Kang, Mee Hye, Kim, Choong-Gon, Kwon, Suk-Tae, Lee, Jehee, Lee, Youn-Ho
• Other Authors: Korea Ocean Research & Development Institute, Sung Kyun Kwan University, Department of Marine Biotechnology, Korea University of Science and Technology
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: endo-beta-1,3-glucanase; laminarinase; antarctic springtail; Cryptopygus antarcticus; glycosyl hydrolase family 16 (GHF16); horizontal gene transfer; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Antarctic; The Antarctic; Antarc*; Antarctic Springtail; antarcticus; Springtail
• Online Access: https://hal.inrae.fr/hal-02660278; https://doi.org/10.1016/j.cbpb.2010.01.003

International audience Collembolan species have been known to have beta-1,3-glucanase activity and yet the genes coding such enzymes have not been demonstrated. We report here a novel arthropod endo-beta-1,3-glucanase gene CaLam from the Antarctic springtail, Cryptopygus antarcticus . The open reading frame consists of 813bp encoding 270 amino acids with a putative signal peptide and a typical motif of glycosyl hydrolase family 16 (GHF16), E-I-D-I-T-E. The recombinant protein expressed in E. coli shows the hydrolytic activity toward laminarin (K(m) approximately 9.98mg/mL) with an optimal temperature 50 degrees C and an optimal pH 6.0. CaLam digests laminarin and laminarioligosaccharides except laminaribiose as an endo-beta-1,3-glucanase, releasing glucose, laminaribiose and laminaritriose as the major products. Analyses of molecular phylogeny of CaLam and its protein structure reveal that CaLam is closely related with bacterial beta-1,3-glucanases more than with the eukaryotic homologues. Even so, the genomic structure of the CaLam gene consisting of six exons interspersed with approximately 57 to 63bp introns confirms that it is endogenous in the genome of the Antarctic springtail. These results suggest that CaLam should have been transferred from bacteria to the lineage of the Collembolan species by horizontal gene transfer.