title: Activity and carboxylation specificity factor of mutant ribulose 1,5-bisphosphate carboxylase/oxygenase from Anacystis nidulans.
abstract: The values of molecular carboxylase activity kcat and carboxylation specificity factor tau for mutant ribulose 1,5-bisphosphate carboxylase (rubisco) from Anacystis nidulans decreased as compared to those of the wild type recombinant rubisco. The substitution of five amino acid residues in rubisco large subunit Lys,Ala,Ser,Thr,Leu(339-343)Phe,Leu,Met,Ile,Lys had kcat decreased by 90% and tau by 36.3%. The same parameters for mutants with the single replacements decreased: for Thr342Ile kcat by 40.5% and tau by 16.7%, and for mutant Leu343Lys kcat by 48.1% and tau by 18.5%. Mutant rubisco with three amino acid residues changed Val,Asp,Leu(346-348)Tyr,His,Thr was inactive. The substitution Leu326Ile decreased kcat by 54.4% and tau by 34.2%; and change Ser328Ala decreased kcat only by 5.6% but tau by 41.5%. Replacement Asn123His decreased kcat by 16.5%. Significance of the non conservative amino acid residues for carboxylase activity and ribulose-1,5-bisphosphate partition is discussed.
authors.affiliation: Institute of Soil Science and Photosynthesis R.A.S., Pushchino Moscow region, Russia.
authors.forename: A K
authors.initials: AK
authors.lastname: Romanova
authors.forename: Z
authors.initials: Z
authors.lastname: Zhen-Qi-Cheng
authors.forename: B A
authors.initials: BA
authors.lastname: McFadden
mesh_terms: D001665:Binding Sites; D000458:Cyanobacteria / Q000201:enzymology* / Q000235:genetics; D017377:Diatoms / Q000201:enzymology; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics* / Q000378:metabolism*; D016415:Sequence Alignment; D013379:Substrate Specificity
chemical_list: D011994:Recombinant Proteins; D012273:Ribulose-Bisphosphate Carboxylase