Enhancement of the thermostability of a recombinant [beta]-agarase, AgaB, from Zobellia galactanivorans by random mutagenesis

• Published in: Biotechnology letters Vol. 32; no. 7; p. 943
• Main Authors: Jang, Min-kyung, Lee, Seung Woo, Lee, Dong-geun, Kim, Nam-young, Yu, Ki Hwan, Jang, Hye Ji, Kim, Suhkman, Kim, Andre, Lee, Sang-hyeon
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Nature B.V 01.07.2010
• Subjects: Cells; Mutation; Thermodynamics
• ISSN: 0141-5492; 1573-6776
• DOI: 10.1007/s10529-010-0237-5

Random mutagenesis was performed on β-agarase, AgaB, from Zobellia galactanivorans to improve its catalytic activity and thermostability. The activities of three mutants E99K, T307I and E99K-T307I were approx. 140, 190 and 200%, respectively, of wild type β-agarase (661 U/mg) at 40°C. All three mutant enzymes were stable up to 50°C and E99K-T307I had the highest thermostability. The melting temperature (T ^sub m^) of E99K-T307I, determined by CD spectra, was increased by 5.2°C over that of the wild-type enzyme (54.6°C). Activities of both the wild-type and E99K-T307I enzymes, as well as their overall thermostabilities, increased in 1 mM CaCl^sub 2^. The E99K-T307I enzyme was stable at 55°C with 1 mM CaCl^sub 2^, reaching 260% of the activity the wild-type enzyme held at 40°C without CaCl^sub 2^.[PUBLICATION ABSTRACT]