Characterization of a Thermostable and Surfactant-Tolerant Chondroitinase B from a Marine Bacterium Microbulbifer sp. ALW1

• Main Authors: Du, X. (Author), Hu, Q. (Author), Jiang, Z. (Author), Li, H. (Author), Li, Z. (Author), Long, L. (Author), Mou, M. (Author), Ni, H. (Author), Zhu, Y. (Author)
• Format: Article
• Language: English
• Published: MDPI 2022
• Subjects: chondroitinase B; Microbulbifer sp; surfactant-tolerant; thermostable
• Online Access: View Fulltext in Publisher

 Chondroitinase plays an important role in structural and functional studies of chondroitin sulfate (CS). In this study, a new member of chondroitinase B of PL6 family, namely ChSase B6, was cloned from marine bacterium Microbulbifer sp. ALW1 and subjected to enzymatic and structural characterization. The recombinant ChSase B6 showed optimum activity at 40◦C and pH 8.0, with enzyme kinetic parameters of Km and Vmax against chondroitin sulfate B (CSB) to be 7.85 µg/mL and 1.21 U/mg, respectively. ChSase B6 demonstrated thermostability under 60◦C for 2 h with about 50% residual activity and good pH stability under 4.0–10.0 for 1 h with above 60% residual activity. In addition, ChSase B6 displayed excellent stability against the surfactants including Tween-20, Tween-80, Trion X-100, and CTAB. The degradation products of ChSase B6-treated CSB exhibited improved antioxidant ability as a hydroxyl radical scavenger. Structural analysis and site-directed mutagenesis suggested that the conserved residues Lys248 and Arg269 were important for the activity of ChSase B6. Characterization, structure, and molecular dynamics simulation of ChSase B6 provided a guide for further tailoring for its industrial application for chondroitin sulfate bioresource development. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.