title: Simultaneous enhanced catalytic activity and thermostability of a 1,3-1,4-β-glucanase from Bacillus amyloliqueformis by chemical modification of lysine residues.
abstract: The thermostablility and enzymatic activity of 1,3-1,4-β-glucanase (BglA) from Bacillus amyloliquefaciens was improved by modifying five (out of 12) ε-amino groups in lysine residues with nitrous acid. The optimal modification condition for BglA was determined as 30 mM nitrous acid at, 40 °C for 30 min. The optimally-modified BglA had higher specific activity and T 50 value, which were 3,370 U/mg and 70 °C, respectively. Its half-life values at 50 and 60 °C were extended and reached 58.5 and 49.5 min, respectively. Circular dichroism analysis showed that the secondary structures in modified BglA were almost the same with that of wild-type BglA. Thus, modification of lysine residues can simultaneously improve the activity and thermostability of β-glucanase which are ideal targets for further protein engineering.
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu, China, Shingtokniu@gmail.com.
authors.forename: Chengtuo
authors.initials: C
authors.lastname: Niu
authors.forename: Linjiang
authors.initials: L
authors.lastname: Zhu
authors.forename: Jinjing
authors.initials: J
authors.lastname: Wang
authors.forename: Qi
authors.initials: Q
authors.lastname: Li
mesh_terms: D001407:Bacillus / Q000201:enzymology*; D002942:Circular Dichroism; D004795:Enzyme Stability / Q000528:radiation effects; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism*; D009608:Nitrous Acid / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D055550:Protein Stability / Q000528:radiation effects; D013696:Temperature; D013997:Time Factors
chemical_list: D006026:Glycoside Hydrolases; C028020:licheninase; D008239:Lysine; D009608:Nitrous Acid