RT Journal Article SR Electronic(1) A1 Kirsch, Friedrich A1 Pade, Nadin A1 Klähn, Stephan A1 Hess, Wolfgang R. A1 Hagemann, MartinYR 2017 T1 The glucosylglycerol-degrading enzyme GghA is involved in acclimation to fluctuating salinities by the cyanobacterium Synechocystis sp. strain PCC 6803 JF Microbiology, VO 163 IS 9 SP 1319 OP 1328 DO https://doi.org/10.1099/mic.0.000518 PB Microbiology Society, SN 1465-2080, AB The ggpS gene, which encodes the key enzyme for the synthesis of the compatible solute glucosylglycerol (GG), has a promoter region that overlaps with the upstream-located gene slr1670 in the cyanobacterium Synechocystissp. PCC 6803. Like ggpS, the slr1670 gene is salt-induced and encodes a putative glucosylhydrolase. A mutant strain with a slr1670 deletion was generated and found to be unable to adapt the internal GG concentrations in response to changes in external salinities. Whereas cells of the wild-type reduced the internal pool of GG when exposed to gradual and abrupt hypo-osmotic treatments, or when the compatible solute trehalose was added to the growth medium, the internal GG pool of ∆slr1670 mutant cells remained unchanged. These findings indicated that the protein Slr1670 is involved in GG breakdown. The biochemical activity of this GG-hydrolase enzyme was verified using recombinant Slr1670 protein, which split GG into glucose and glycerol. These results validate that Slr1670, which was named GghA, acts as a GG hydrolase. GghA is involved in GG turnover in fluctuating salinities, and similar proteins are found in the genomes of other GG-synthesizing cyanobacteria., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.000518