Gas Vesicle Nanoparticles

Abstract

Gas vesicles are intracellular nanoparticles produced by many prokaryotic microorganisms. These buoyant, gas‐filled and phase‐bright organelles promote movement of cells vertically in the water column. Easily isolated by flotation after cell disruption, the nanoparticles are surrounded by a lipid‐free protein membrane that is extremely stable and gas permeable. Gas vesicle biogenesis begins with small bicones and proceeds to longer spindle or cylindrical‐shaped structures, with the size and shape dependent on the species. Water is excluded from the gas vesicle interior as a consequence of hydrophobicity of the inner surface of the membrane. Two major and five minor gas vesicle proteins coded by large gvp ( g as v esicle p rotein) gene clusters with a dozen or more genes have been found in many species. Such gene clusters are necessary and sufficient for biogenesis. Research on gas vesicle architecture is ongoing, and gas vesicle nanoparticles are being engineered for uses in environmental and biomedical applications. Diverse prokaryotes make organelles known as gas vesicles (GVs) for buoyancy. Gas vesicles are common in cyanobacteria, halophilic Archaea and other aquatic microorganisms. Toxic blooms are made by some gas vesicle‐containing cyanobacteria. Buoyancy increases the availability of light and oxygen to cells for photosynthesis and respiration. Gas vesicle synthesis requires a cluster of about a dozen genes. Gas vesicles are easily purified and harvested as nanoparticles (GVNPs). GVNPs are extremely stable and may be genetically engineered to display foreign proteins. The GVNPs are being developed for biomedical and environmental applications.

Genome Sequence of the Early 20th-Century Extreme Halophile Halobacterium sp. Strain NRC-34001

“…Based on additional in-house analysis using GeneMark.hmm 2, FeatureExtract, Sequence Manipulation Suite, and EMBOSS ( 21 – 24 ), all 799 conserved core haloarchaeal groups (cHOGs), 6 Orc/Cdc6 proteins, 3 TATA-binding proteins, and 4 TFB proteins ( 25 – 28 ) were found, as well as genes coding for bacteriorhodopsin, halorhodopsin, and sensory rhodopsins 1 and 2 ( 29 , 30 ). The genome also includes a complete buoyant gas vesicle nanoparticle (GVNP) gene cluster, although the strain has not been shown to produce GVNPs ( 31 , 32 ).…”

Genome Sequence of Halobacterium sp. Strain BOL4-2, Isolated and Cultured from Salar de Uyuni, Bolivia

“…The genome encodes all 799 conserved core haloarchaeal groups (cHOGs) ( 25 ), 10 Orc/Cdc6 proteins, a TATA-binding protein, and 7 transcription factor B (TFB) proteins ( 26 – 29 ). Also encoded are the retinal proteins bacteriorhodopsin, halorhodopsin, and sensory rhodopsin 2 ( 30 ) and buoyant gas vesicle nanoparticles ( 31 , 32 ). The methylated DNA motifs (with methylated base underlined) recorded in the REBASE database include C TAG (m4C), GT C ACG (m4C), CG A YNNNNNNGTRC/GY A CNNNNNNRTCG (m6A), and AGC A NNNNNNCTG/C A GNNNNNNTGCT (m6A) ( 33 ).…”

Genome Sequence and Methylation Pattern of Haloterrigena salifodinae BOL5-1, an Extremely Halophilic Archaeon from a Bolivian Salt Mine

“…The proteome was highly acidic (2), with a calculated mean pI value of 4.64, and nearly all of the core haloarchaeal orthologous groups (cHOGs) were present (20)(21)(22). The BOL5-1 genome contained expanded gene families, e.g., Orc/Cdc6, TATA-binding, and TFB protein genes (23), and a gene cluster for gas vesicle nanoparticles (24,25) on the chromosome. The genome also encoded transposase genes, suggesting the presence of ISH elements (26).…”