To be or not to be a compatible solute: Bioversatility of mannosylglycerate and...

• Author(s): Empadinhas, Nuno ; Costa, Milton S. da
• Date: 2008
• Persistent ID: http://hdl.handle.net/10316/3852
• Origin: Estudo Geral - Universidade de Coimbra
• Subject(s): Compatible solutes; Mannosylglycerate; Glucosylglycerate; Biosynthesis
• Document Type: Article
• Language: English

Description

Mannosylglycerate (MG) is an intracellular organic solute found in some red algae, and several thermophilic bacteria and hyperthermophilic archaea. Glucosylglycerate (GG) was identified at the reducing end of a polysaccharide from mycobacteria and in a free form in a very few mesophilic bacteria and halophilic archaea. MG has a genuine role in the osmoadaptation and possibly in thermal protection of many hyper/thermophilic bacteria and archaea, but its role in red algae, where it was identified long before hyperthermophiles were even known to exist, remains to be clarified. The GG-containing polysaccharide was initially detected in Mycobacterium phlei and found to regulate fatty acid synthesis. More recently, GG has been found to be a major compatible solute under salt stress and nitrogen starvation in a few microorganisms. This review summarizes the occurrence and physiology of MG accumulation, as well as the distribution of GG, as a free solute or associated with larger macromolecules. We also focus on the recently identified pathways for the synthesis of both molecules, which were elucidated by studying hyper/thermophilic MG-accumulating organisms. The blooming era of genomics has now allowed the detection of these genes in fungi and mosses, opening a research avenue that spans the three domains of life, into the role of these two sugar derivatives. http://www.sciencedirect.com/science/article/B7GVX-4SWP1Y0-1/1/21fa8b34b94c7aee64e8337e26bd247c