title: The quaternary structure of the recombinant bovine odorant-binding protein is modulated by chemical denaturants.
abstract: A large group of odorant-binding proteins (OBPs) has attracted great scientific interest as promising building blocks in constructing optical biosensors for dangerous substances, such as toxic and explosive molecules. Native tissue-extracted bovine OBP (bOBP) has a unique dimer folding pattern that involves crossing the α-helical domain in each monomer over the other monomer's β-barrel. In contrast, recombinant bOBP maintaining the high level of stability inherent to native tissue bOBP is produced in a stable native-like state with a decreased tendency for dimerization and is a mixture of monomers and dimers in a buffered solution. This work is focused on the study of the quaternary structure and the folding-unfolding processes of the recombinant bOBP in the absence and in the presence of guanidine hydrochloride (GdnHCl). Our results show that the recombinant bOBP native dimer is only formed at elevated GdnHCl concentrations (1.5 M). This process requires re-organizing the protein structure by progressing through the formation of an intermediate state. The bOBP dimerization process appears to be irreversible and it occurs before the protein unfolds. Though the observed structural changes for recombinant bOBP at pre-denaturing GdnHCl concentrations show a local character and the overall protein structure is maintained, such changes should be considered where the protein is used as a sensitive element in a biosensor system.
authors.affiliation: Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg, Russia.
authors.forename: Olga V
authors.initials: OV
authors.lastname: Stepanenko
authors.affiliation: Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg, Russia.
authors.forename: Olesya V
authors.initials: OV
authors.lastname: Stepanenko
authors.affiliation: Laboratory for Molecular Sensing, IBP-CNR, Naples, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Staiano
authors.affiliation: Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg, Russia ; St. Petersburg State Polytechnical University, St. Petersburg, Russia.
authors.forename: Irina M
authors.initials: IM
authors.lastname: Kuznetsova
authors.affiliation: Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg, Russia.
authors.forename: Konstantin K
authors.initials: KK
authors.lastname: Turoverov
authors.affiliation: Laboratory for Molecular Sensing, IBP-CNR, Naples, Italy.
authors.forename: Sabato
authors.initials: S
authors.lastname: D'Auria
mesh_terms: D000818:Animals; D002417:Cattle; D008958:Models, Molecular; D011489:Protein Denaturation; D020836:Protein Structure, Quaternary; D018035:Receptors, Odorant / Q000737:chemistry*; D011994:Recombinant Proteins
chemical_list: D018035:Receptors, Odorant; D011994:Recombinant Proteins; C045648:odorant-binding protein