The quaternary structure of the recombinant bovine odorant-binding protein is modulated by chemical denaturants

PLoS One. 2014 Jan 7;9(1):e85169. doi: 10.1371/journal.pone.0085169. eCollection 2014.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle
  • Models, Molecular
  • Protein Denaturation*
  • Protein Structure, Quaternary*
  • Receptors, Odorant / chemistry*
  • Recombinant Proteins*

Substances

  • Receptors, Odorant
  • Recombinant Proteins
  • odorant-binding protein

Grants and funding

This work was supported in part by the Program MCB RAS (Konstantin K. Turoverov), the Scholarships from the President of RF (Olga V. Stepanenko and Olesya V. Stepanenko), and the Program of Cooperation between RAS and CNR (Sabato D’Auria and Konstantin K. Turoverov). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.