title: Identification of residues important for the activity of aldehyde-deformylating oxygenase through investigation into the structure-activity relationship.
abstract: Aldehyde-deformylating oxygenase (ADO) is a key enzyme involved in the biosynthetic pathway of fatty alk(a/e)nes in cyanobacteria. However, cADO (cyanobacterial ADO) showed extreme low activity with the kcatvalue below 1 min-1, which would limit its application in biofuel production. To identify the activity related key residues of cADO is urgently required.
  
  
  
  The amino acid residues which might affect cADO activity were identified based on the crystal structures and sequence alignment of cADOs, including the residues close to the di-iron center (Tyr39, Arg62, Gln110, Tyr122, Asp143 of cADO-1593), the protein surface (Trp 178 of cADO-1593), and those involved in two important hydrogen bonds (Gln49, Asn123 of cADO-1593, and Asp49, Asn123 of cADO-sll0208) and in the oligopeptide whose conformation changed in the absence of the di-iron center (Leu146, Asn149, Phe150 of cADO-1593, and Thr146, Leu148, Tyr150 of cADO-sll0208). The variants of cADO-1593 from Synechococcus elongatus PCC7942 and cADO-sll0208 from Synechocystis sp. PCC6803 were constructed, overexpressed, purified and kinetically characterized. The kcatvalues of L146T, Q49H/N123H/F150Y and W178R of cADO-1593 and L148R of cADO-sll0208 were increased by more than two-fold, whereas that of R62A dropped by 91.1%. N123H, Y39F and D143A of cADO-1593, and Y150F of cADO-sll0208 reduced activities by ≤ 20%.
  
  
  
  Some important amino acids, which exerted some effects on cADO activity, were identified. Several enzyme variants exhibited greatly reduced activity, while the kcatvalues of several mutants are more than two-fold higher than the wild type. This study presents the report on the relationship between amino acid residues and enzyme activity of cADOs, and the information will provide a guide for enhancement of cADO activity through protein engineering.
authors.affiliation: Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Luyao
authors.initials: L
authors.lastname: Bao
authors.affiliation: University of Chinese Academy of Sciences, Beijing, 100049, China.|National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Chenjun
authors.initials: C
authors.lastname: Jia
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Li
authors.affiliation: Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China. jjli@ipe.ac.cn.|Present Address: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China. jjli@ipe.ac.cn.
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: Li
authors.affiliation: Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China. lvxf@qibebt.ac.cn.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Lu
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000596:Amino Acids / Q000737:chemistry*; D001665:Binding Sites; D019295:Computational Biology; D003198:Computer Simulation; D004789:Enzyme Activation; D004795:Enzyme Stability; D008956:Models, Chemical; D010105:Oxygenases / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D046940:Synechococcus / Q000201:enzymology*
chemical_list: D000447:Aldehydes; D000596:Amino Acids; D010105:Oxygenases
keywords: Aldehyde-deformylating oxygenase; Fatty alk(a/e)ne; Site-directed mutagenesis; Structure-activity relationship; Synechococcus elongatus PCC7942; Synechocystis sp. PCC6803