A dual-functional peptide, Kpt from Ruegeria pomeroyi DSS-3 for protein purification and silica precipitation

Abstract

Marine biological resources are significant sources of biological and chemical processes and principles from which new bioactive compounds can be explored. Here, we report a new silica-forming peptide (SFP) called Kpt (KPTHHHHHHDG) derived from a membrane protein in Ruegeria pomeroyi DSS-3, a heterotrophic marine bacterium found in coastal areas. The imidazole-, hydroxy-groups, and high positive charge of the Kpt sequence contribute to silica precipitation. Kpt exhibited high silica-precipitating activity at a pH 8.0 compared to other SFPs. Additionally, Kpt sustained its activity when was fused to N-terminus of ferritin (Fn), forming Kpt-Fn with unchanged caged structure. The results of this study suggest that Kpt can be used as a new SFP and a purification tag in fusion proteins by affinity chromatography. With its short sequence, Kpt is expected to have no effect on the main protein structure, which was fused by Kpt. Therefore, it is an ideal peptide for producing multifunctional biomolecules.