Download MendeleyA thermostable and highly active fungal GH3 beta-glucosidase generated by random and saturation mutagenesis.
Matsuzaki, C., Hidaka, M., Nakashima, Y., Honda, Y., Koyanagi, T., Ishikawa, K., Katoh, T., Katayama, T., Kumagai, H.(2025) Proc Jpn Acad Ser B Phys Biol Sci 101: 177-195
- PubMed: 39971319
- DOI: https://doi.org/10.2183/pjab.101.011
- Primary Citation of Related Structures:
8Y0L, 8Y0M - PubMed Abstract:
Enhancing the thermostability of cellulose-degrading enzymes is pivotal for establishing an efficient bioconversion system from cellulosic materials to value-added compounds. Here, by introducing random and saturation mutagenesis into the Thermoascus aurantiacus β-glucosidase gene, we generated a hyperthermostable mutant with five amino acid substitutions. Analysis of temperature-induced unfolding revealed the involvement of each replacement in the increased T m value. Structural analysis showed that all replacements are located at the periphery of the catalytic pocket. D433N replacement, which had a pronounced thermostabilizing effect (ΔT m ＝ 4.5°C), introduced an additional hydrogen bond with a backbone carbonyl oxygen in a long loop structure. The mutant enzyme expressed in Kluyveromyces marxianus exhibited a T m of 82°C and hydrolyzed cellobiose with k cat and K m values of 200 s －1 and 1.8 mM, respectively. When combined with a thermostable endoglucanase, the mutant enzyme released 20％ more glucose than wild-type enzyme from cellulosic material. The mutant enzyme is therefore a noteworthy addition to the existing repertoire of thermostable β-glucosidases.
- Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Nonoichi, Ishikawa, Japan.
Organizational Affiliation:
