Synthesis of glycerophosphorylated cyclic (1,2)-beta-glucans in Rhizobium meliloti strain 1021 after osmotic shock.
The transfer of phosphoglycerol moieties from phosphatidylglycerol to the cyclic (1,2)-beta-glucans in growing cultures of Rhizobium meliloti strain 1021 was investigated using pulse-chase experiments with [3H]glycerol and/or [14C]glucose. No transfer occurred when cells were grown and pulse-chased in a medium containing 0.4 M NaCl. However, radiolabelled glycerophosphorylated cyclic (1,2)-beta-glucans could be detected within 30 min after transfer of these cultures to a low-osmolarity medium. Conversely, when low-osmolarity cultures were shifted to a high-osmolarity medium containing 0.4 M NaCl or 0.8 M sucrose, the transfer of phosphoglycerol substituents to the cyclic (1,2)-beta-glucans was inhibited. Further experiments revealed that the transfer of phosphoglycerol substituents to the cyclic (1,2)-beta-glucans occurs within the periplasmic compartment.
Breedveld
M W
MW
Department of Food Science, Pennsylvania State University, University Park 16802.
Miller
K J
KJ
D002462:Cell Membrane / Q000378:metabolism; D003470:Culture Media; D005936:Glucans / Q000096:biosynthesis* / Q000737:chemistry; D005994:Glycerophosphates / Q000737:chemistry; D009997:Osmotic Pressure; D010766:Phosphorylation; D016962:Sinorhizobium meliloti / Q000378:metabolism*; D047071:beta-Glucans
D003470:Culture Media; D005936:Glucans; D005994:Glycerophosphates; D047071:beta-Glucans; C080135:cyclic beta(1-2)glucan