title: Characterization and mechanism insight of accelerated catalytic promiscuity of Sulfolobus tokodaii (ST0779) peptidase for aldol addition reaction.
abstract: A novel peptidase from thermophilic archaea Sulfolobus tokodaii (ST0779) is examined for its catalytic promiscuity of aldol addition, which shows comparable activity as porcine pancreatic lipase (PPL, one of the best enzymes identified for biocatalytic aldol addition) at 30 °C but much accelerated activity at elevated temperature. The molecular catalytic efficiency kcat/Km (M(-1) s(-1)) of this thermostable enzyme at 55 °C adds up to 140 times higher than that of PPL at its optimum temperature 37 °C. The fluorescence quenching analysis depicts that the binding constants of PPL are significantly higher than those of ST0779, and their numbers of binding sites show opposite temperature dependency. Thermodynamic parameters estimated by fluorescence quenching analysis unveil distinctly different substrate-binding modes between PPL and ST0779: the governing binding interaction between PPL and substrates is hydrophobic force, while the dominating substrate-binding forces for ST0779 are van der Waals and H-bonds interactions. A reasonable mechanism for ST0779-catalyzed aldol reaction is proposed based on kinetic study, spectroscopic analysis, and molecular stereostructure simulation. This work represents a successful example to identify a new enzyme for catalytic promiscuity, which demonstrates a huge potential to discover and exploit novel biocatalyst from thermophile microorganism sources.
authors.affiliation: Key Laboratory for Molecular Enzymology and Engineering, The Ministry of Education, Jilin University, Changchun, 130021, China.|Department of Engineering, Faculty of Science and Technology, Aarhus University, Gustav Wied Vej 10, Aarhus, 8000, Denmark.
authors.forename: Rong
authors.initials: R
authors.lastname: Li
authors.affiliation: Department of Engineering, Faculty of Science and Technology, Aarhus University, Gustav Wied Vej 10, Aarhus, 8000, Denmark.
authors.forename: Bianca
authors.initials: B
authors.lastname: Perez
authors.affiliation: Key Laboratory for Molecular Enzymology and Engineering, The Ministry of Education, Jilin University, Changchun, 130021, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Jian
authors.affiliation: Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark.
authors.forename: Mads Mørk
authors.initials: MM
authors.lastname: Jensen
authors.affiliation: Key Laboratory for Molecular Enzymology and Engineering, The Ministry of Education, Jilin University, Changchun, 130021, China. gaorj@jlu.edu.cn.
authors.forename: Renjun
authors.initials: R
authors.lastname: Gao
authors.affiliation: Interdisciplinary Nanoscience Center, Aarhus University, Gustav Wieds Vej 14, 8000, Aarhus C, Denmark.
authors.forename: Mingdong
authors.initials: M
authors.lastname: Dong
authors.affiliation: Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark.
authors.forename: Marianne
authors.initials: M
authors.lastname: Glasius
authors.affiliation: Department of Engineering, Faculty of Science and Technology, Aarhus University, Gustav Wied Vej 10, Aarhus, 8000, Denmark. guo@mb.au.dk.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Guo
mesh_terms: D000447:Aldehydes / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D010447:Peptide Hydrolases / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation; D013057:Spectrum Analysis; D016944:Sulfolobus / Q000201:enzymology*; D013696:Temperature
chemical_list: D000447:Aldehydes; C116609:3-hydroxybutanal; D010447:Peptide Hydrolases
keywords: Aldol reaction; Biocatalysis; Catalytic promiscuity; Fluorescence spectroscopy; Hydrolase; Sulfolobus tokodaii peptidase (ST0779)