Theoretical calculation on degradation mechanism of novel copolyesters under CALB enzyme  

作　　者：Yuanyang Ren Zhiwen Cheng Luwei Cheng Yawei Liu Mingyue Li Tao Yuan Zhemin Shen 

机构地区：[1]School of Environmental Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China [2]State Environmental Protection Key Laboratory of Environmental Health Impact Assessment of Emerging Contaminants,Shanghai 200240,China [3]Shanghai Institute of Pollution Control and Ecological Security,Shanghai 200092,China

出　　处：《Journal of Environmental Sciences》2025年第3期242-253,共12页环境科学学报(英文版)

基　　金：supported by the Joint Funds of the National Natural Science Foundation of China(No.U21A20320);the National Natural Science Foundation of China(No.22106102);was also sponsored by the special fund of State Environmental Protection Key Laboratory of Environmental Health Impact Assessment of Emerging Contaminants(No.SEPKLEHIAEC-202203).

摘　　要：Poly(butylene succinate-co-furandicarboxylate)(PBSF)and poly(butylene adipateco-furandicarboxylate)(PBAF)are novel furandicarboxylic acid-based biodegradable copolyesters with great potential to replace fossil-derived terephthalic acid-based copolyesters such as poly(butylene succinate-co-terephthalate)(PBST)and poly(butylene adipate-co-terephthalate)(PBAT).In this study,quantum chemistry techniques after molecular dynamics simulations are employed to investigate the degradationmechanism of PBSF and PBAF catalyzed by Candida antarctica lipase B(CALB).Computational analysis indicates that the catalytic reaction follows a four-step mechanism resembling the ping-pong bibi mechanism,with the initial two steps being acylation reactions and the subsequent two being hydrolysis reactions.Notably,the first step of the hydrolysis is identified as the rate-determining step.Moreover,by introducing single-point mutations to expand the substrate entrance tunnel,the catalytic distance of the first acylation step decreases.Additionally,energy barrier of the rate-determining step is decreased in the PBSF system by site-directed mutations on key residues increasing hydrophobicity of the enzyme’s active site.This study unprecedently show the substrate binding pocket and hydrophobicity of the enzyme’s active site have the potential to be engineered to enhance the degradation of copolyesters catalyzed by CALB.

关 键 词：Poly(butylene succinate-co-furandicarboxylate) Poly(butylene adipate-co-furandicarboxylate) Candida antarctica lipase B Degradation mechanism Site-directed mutations 

分 类 号：X703[环境科学与工程—环境工程]