Isolation, biochemical characterization and anti-bacterial activity of BPIFA2 protein

Abstract

Objective: Human BPIFA2 (parotid secretory protein) is a ubiquitous soluble salivary protein, which belongs to the PLUNC family of proteins. Having sequence similarity to bactericidal/permeability-increasing protein and lipopolysaccharide-binding protein, PLUNC proteins are probably involved in local antibacterial response at mucosal sites, such as oral cavity. The aim of the study was to isolate and characterize human BPIFA2. Design: In this paper, we report one-step affinity chromatography method for BPIFA2 purification from whole human saliva. The isolated BPIFA2 was identified by trypsin mass fingerprinting and characterized by electrophoretic methods. Antibacterial activity of BPIFA2 against model microorganism Pseudomonas aeruginosa was shown in minimum inhibitory concentration and time kill study assays. Results: The protein showed microheterogeneity, both in molecular weight and pI value. BPIFA2 inhibited the growth of P. aeruginosa in microgram concentration range determined by minimum inhibitory concentration assay. In the time kill study, 32 mu g/mL BPIFA2 showed clear bactericidal activity and did not cause any aggregation of bacteria. Conclusion: Affinity chromatography is well suited for isolation of functional BPIFA2 with a potent bactericidal activity against P. aeruginosa.