Introduction

Vertebrate Odorant Binding Proteins (OBP) bind compounds involved in the pathogenic mechanisms (Quorum Sensing Molecules like Acyl homoserine lactones and farnesol, or the toxin pyocyanin) of bacteria and fungi (included P. aeruginosa and C. albicans), and inhibit their growth. Hence this patent proposes OBPs as antimicrobial agents alternative or co-adjuvants to antibiotics and antimycotics.

Technical features

Vertebrate OBPs are secretory protein scavengers whose function is the removal of endogenous and xenobiotic bioactive compounds, whose activities might affect tissue homeostasis. On this basis, we verified on one side if bovine and porcine OBP (both native and tagged with histidines at the NH2 terminal) can bind bacterial toxins (pyocyanin) and compounds involved in chemical communication (quorum sensing molecules, like Acyl-homoserine lactones and farnesol) between microorganisms, and on the other if they can inhibit their growth (Time Kill assays – TKA). The positivity of both ligand binding tests and TKAs for P. aeruginosa, C. albicans  and other microorganisms, design OBPs as antimicrobial agents that can be employed as an alternative, or in combination, to antibiotics and antimycotics.
1 – Bianchi et al. PLOS ONE 14(3): e0213545, (2019).

Possible Applications

• OBPs can be applied simultaneously against bacteria and fungi;
• OBPs could be employed for pathogens resistant to antibiotics, like P. aeruginosa, that is the bacterium responsible of several fatal nosocomial infections, as well as of most of the infections in charge of patients affected by cystic fibrosis;
• OBPs are natural proteins suitable for the packaging of food products.

Advantages

• OBPs are antimicrobial that do not induce antibiotic resistance;
• OBPs are biological products;
• OBPs can be produced recombinant at high yields in E. coli;
• The OBP forms tagged with histidines at the amino-terminal exhibit enhanced antimicrobial activities;
• They can be applied either in solution or coupled to a solid matrix (agarose).