Functional Inclusions in Prokaryotic Cells

This chapter reviews the functional inclusions in prokaryotic cells. Inclusions are visible expressions of cell metabolism. The inclusion is an integral part of the cell's metabolic machinery, it is important in adjusting the environment of the cell, thereby regulating certain metabolic events, or might represent a product of the cell's metabolism. Gas vesicles are rigid shells of protein that are found in a wide variety of prokaryotic organisms. The protein subunits of the gas vesicle have unique properties that enable their association to result in a structure that is impermeable to water. The genes encoding the structural components of the phycobilisome, gas vesicle, andthe genes for the enzymes involved in glycogen biosynthesis are cloned and sequenced. Site-directed mutagenesis provides valuable information relating to the molecular mechanisms of catalysis and allosteric regulation. The organization of the genes for a given inclusion is determined and is found to be clustered on the chromosome.