Bioengineering novel floating nanoparticles for protein and drug delivery

Abstract

Gas vesicle nanoparticles (GVNPs) are hollow protein nanoparticles produced by Halobacterium sp. NRC-1 which are being engineered for protein delivery. To advance the bioengineering potential of GVNPs, a strain of NRC-1 deleted for the gvpC gene (ΔgvpC) was constructed and a synthetic gene coding for Gaussia princeps luciferase was fused to an abbreviated gvpC gene on an expression plasmid. When introduced into theΔgvpC strain, an active GvpC-luciferase fusion protein bound to GVNPs resulted. These results represent both a technical improvement in the GVNP display system and its expansion for the display of active enzymes.

Keywords: Gas vesicle naoparticles (GVNPs); Gaussia princeps; enzyme display; luciferase; vaccine.

Figure 1

Construction of an improved genetic system for expression of foreign proteins fused to GvpC and display on GVNPs. A. Halobacterium sp. NRC-1 gene cluster for synthesis of GVNPs, showing leftward transcribed genes in blue and rightward transcribed genes in red and white. The gvpC gene was deleted in Halobacterium sp. NRC-1 Δura3ΔgvpC, with the deleted region labelled Δin white. B. Plasmid pDRK-C3-luc with locations of genes marked by circular arrows (bla, β-lactamase; mev, mevinolin-resistance; gvpC3, coding for C3 fragment of GvpC, luc, codon-optimized luciferase gene, rep, replicase), promoter marked P, and location of restriction sites indicated.

Figure 2

Luciferase activity in strain Halobacterium sp. NRC-1Δura3ΔgvpC (pDRK-C3-luc). A. Background signal. B. Signal in GVNPs purified by flotation. C. Signal after freezing and thawing. Standard deviations of 4 assays are shown with error bars indicated. Y Axis: 10³ RLU.