Download MendeleyMolecular insights into substrate promiscuity of CotA laccase catalyzing lignin-phenol derivatives.
Li, J., Liu, Z., Zhao, J., Wang, G., Xie, T.(2023) Int J Biol Macromol 256: 128487-128487
- PubMed: 38042324
- DOI: https://doi.org/10.1016/j.ijbiomac.2023.128487
- Primary Citation of Related Structures:
7Y8B, 7Y8C - PubMed Abstract:
CotA laccases are multicopper oxidases known for promiscuously oxidizing a broad range of substrates. However, studying substrate promiscuity is limited by the complexity of electron transfer (ET) between substrates and laccases. Here, a systematic analysis of factors affecting ET including electron donor acceptor coupling (Η DA ), driving force (ΔG) and reorganization energy (λ) was done. Catalysis rates of syringic acid (SA), syringaldehyde (SAD) and acetosyringone (AS) (kcat(SAD) > kcat(SA) > kcat(AS)) are not entirely dependent on the ability to form phenol radicals indicated by ΔG and λ calculated by Density Functional Theory (SA < SAD ≈ AS). In determined CotA/SA and CotA/SAD structures, SA and SAD bound at 3.9 and 3.7 Å away from T1 Cu coordinating His419 ensuring a similar Η DA . Abilities of substrate to form phenol radicals could mainly account for difference between kcat(SAD) and kcat(SA). Furthermore, substrate pocket is solvent exposed at the para site of substrate's phenol hydroxyl, which would destabilize binding of AS in the same orientation and position resulting in low kcat. Our results indicated shallow partially covered binding site with propensity of amino acids distribution might help CotA discriminate lignin-phenol derivatives. These findings give new insights for developing specific catalysts for industrial application.
Organizational Affiliation:
Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Key Laboratory of Environmental Microbiology of Sichuan Province, Chengdu 610041, China; University of Chinese Academy of Sciences, Beijing 100049, China.
