Functional compartmentalization and metabolic separation in a prokaryotic cell
Jennifer Flechsler, Thomas Heimerl, Harald Huber, Reinhard Rachel, Ivan A. Berg
Abstract
Significance In a typical prokaryotic cell, hundreds of metabolites are present and interconverted simultaneously, some serving as allosteric regulators for unrelated reactions or accidental substrates for promiscuous enzymes or being downright reactive and toxic. Although certain spatial separation of prokaryotic cells has long been proposed, only few examples are known. In many bacteria, the key carboxylase of the Calvin–Benson cycle is located in carboxysomes to concentrate CO 2 and deplete O 2 , while other enzymes of the cycle are in the cytoplasm. The archaeon Ignicoccus hospitalis exhibits a two-membrane structure with an energized outer membrane. Here, we show that CO 2 fixation in this organism takes place in a peripheric cytoplasmic compartment, being separated from information processing occurring in the central cytoplasmic compartment.