Energy Metabolism in Low-temperature and Frozen Conditions in Cold-adapted Microorganisms
from: Cold-Adapted Microorganisms (Edited by: Isao Yumoto). Caister Academic Press, U.K. (2013)
Managing biochemical energy is a challenge that microorganisms have to face for maintaining activity at low temperatures, at which metabolic processes are altered by the decrease of reactions rates and by the rigidification of cellular structures, notably enzymes and membranes. Cold-adapted prokaryotes and eukaryotes, while exhibiting distinct trophic modes, share specificities for compensating these thermodynamic effects and keep the cellular machinery running: they elevate the concentration of adenylate compounds, the key molecules of the energy metabolism. This is achieved by tight adjustments acting at several levels of the metabolism in a global strategy of energy saving: strong orientation of the adenylate metabolism toward the production and regeneration of AMP and its phosphorylation, whereas its destruction is repressed; elevation of the respiration rate; intervention of specific enzymes allowing the rapid synthesis of ATP (polyphosphatases and interferases), shifts in the utilization of substrates; and rerouting of central metabolic pathways. These are presented here and illustrated by examples of metabolic regulations in cold-adapted microorganisms evidenced by recent transcriptomic and proteomic approaches read more ...