A precise swaying map for how promiscuous cellobiose-2-epimerase operate bi-reaction.
Feng, Y., Lyu, X., Cong, Y., Miao, T., Fang, B., Zhang, C., Shen, Q., Matthews, M., Fisher, A.J., Zhang, J.Z.H., Zhang, L., Yang, R.(2023) Int J Biol Macromol 253: 127093-127093
- PubMed: 37758108 
- DOI: https://doi.org/10.1016/j.ijbiomac.2023.127093
- Primary Citation of Related Structures:  
8WBU, 8WBV - PubMed Abstract: 
Promiscuous enzymes play a crucial role in organism survival and new reaction mining. However, comprehensive mapping of the catalytic and regulatory mechanisms hasn't been well studied due to the characteristic complexity. The cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus (CsCE) with complex epimerization and isomerization was chosen to comprehensively investigate the promiscuous mechanisms. Here, the catalytic frame of ring-opening, cis-enediol mediated catalysis and ring-closing was firstly determined. To map the full view of promiscuous CE, the structure of CsCE complex with the isomerized product glucopyranosyl-β1,4-fructose was determined. Combined with computational calculation, the promiscuity was proved a precise cooperation of the double subsites, loop rearrangement, and intermediate swaying. The flexible loop was like a gear, whose structural reshaping regulates the sway of the intermediates between the two subsites of H377-H188 and H377-H247, and thus regulates the catalytic directions. The different protonated states of cis-enediol intermediate catalyzed by H188 were the key point for the catalysis. The promiscuous enzyme tends to utilize all elements at hand to carry out the promiscuous functions.
- Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China; State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 214122 Wuxi, China.
Organizational Affiliation: