ProX from marine Synechococcus spp. show a sole preference for glycine-betaine with differential affinity between ecotypes.

Autor: Ford BA; School of Natural Sciences, Macquarie University, Sydney, Australia., Ranjit P; School of Natural Sciences, Macquarie University, Sydney, Australia., Mabbutt BC; School of Natural Sciences, Macquarie University, Sydney, Australia., Paulsen IT; School of Natural Sciences, Macquarie University, Sydney, Australia.; ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia., Shah BS; School of Natural Sciences, Macquarie University, Sydney, Australia.; ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia.
Jazyk: angličtina
Zdroj: Environmental microbiology [Environ Microbiol] 2022 Dec; Vol. 24 (12), pp. 6071-6085. Date of Electronic Publication: 2022 Aug 28.
DOI: 10.1111/1462-2920.16168
Abstrakt: Osmotic stress, caused by high or fluctuating salt concentrations, is a crucial abiotic factor affecting microbial growth in aquatic habitats. Many organisms utilize common responses to osmotic stress, generally requiring active extrusion of toxic inorganic ions and accumulation of compatible solutes to protect cellular machinery. We heterologously expressed and purified predicted osmoprotectant, proline/glycine betaine-binding proteins (ProX) from two phylogenetically distinct Synechococcus spp. MITS9220 and WH8102. Homologues of this protein are conserved only among Prochlorococcus LLIV and Synechococcus clade I, III and CRD1 strains. Our biophysical characterization show Synechococcus ProX exists as a dimer, with specificity solely for glycine betaine but not to other osmoprotectants tested. We discovered that MITS9220_ProX has a 10-fold higher affinity to glycine betaine than WH8102_ProX, which is further elevated (24-fold) in high salt conditions. The stronger affinity and effect of ionic strength on MITS9220_ProX glycine betaine binding but not on WH8102_ProX alludes to a novel regulatory mechanism, providing critical functional insights into the phylogenetic divergence of picocyanobacterial ProX proteins that may be necessary for their ecological success.
(© 2022 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.)
Databáze: MEDLINE
Externí odkaz: