title: His267 is involved in carbamylation and catalysis of RuBisCO-like protein from Bacillus subtilis.
abstract: Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and RuBisCO-like protein (RLP) from Bacillus subtilis catalyze mechanistically similar enolase reactions. Both enzymes require carbamylation of the ε-amino group of the active site lysine during activation to generate the binding site of the essential Mg(2+) ion. His267 forms a possible hydrogen bond with the carbamate of the active site Lys176 in B. subtilis RLP. This active site histidine is completely conserved in RLPs and RuBisCO. H267Q, H267N and H267A mutant enzymes required higher CO(2) concentrations for maximal activity than wild-type enzyme, suggesting that the histidine is involved in high affinity for activator CO(2) in Bacillus RLP. These mutations showed weak effects on the catalysis of RLP, whereas this residue is reportedly essential for catalysis in RuBisCO but is not involved in the carbamylation. The different functions of the active site histidine in RLP and RuBisCO are discussed.
authors: Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, Nara 630-0192, Japan.
authors: Toshihiro
authors: T
authors: Nakano
authors: Yohtaro
authors: Y
authors: Saito
authors: Akiho
authors: A
authors: Yokota
authors: Hiroki
authors: H
authors: Ashida
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002384:Catalysis; D020134:Catalytic Domain / Q000235:genetics; D006639:Histidine / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D006639:Histidine; D012273:Ribulose-Bisphosphate Carboxylase