Competitive accumulation of betaines by Escherichia coli K-12 and derivative strains lacking betaine porters.
Escherichia coli was grown in hyperosmotic media containing both glycine betaine and one other betaine. E. coli K-12 derivative WG439 (putP- proP- proU-) did not accumulate any of 15 betaines. Strains WG445 (putP- proP- proU+), WG443 (putP- proP+ proU-) and the control strains all accumulated less betaine, (CH3)3N(+)-(CH2)n-COO-, when n was greater than 1. Accumulation was not detectable when n = 5. Both L- and D-isomers of alpha-substituted betaines were accumulated by both strains WG443 and WG445, the D-isomers more slowly. Hydroxylated alpha-substituted betaines were accumulated relatively more through the osmoregulated transport protein ProU than through ProP. In actively growing cultures glycine betaine appeared to be the preferred substrate for accumulation, but the proportion of the second accumulated betaine increased as cultures approached stationary phase.
Randall
K
K
Department of Clinical Biochemistry, Christchurch Hospital, New Zealand.
Lever
M
M
Peddie
B A
BA
Chambers
S T
ST
D026905:Amino Acid Transport Systems; D001426:Bacterial Proteins / Q000378:metabolism; D001622:Betaine / Q000031:analogs & derivatives* / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D003470:Culture Media; D015195:Drug Design; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins; D050485:GABA Plasma Membrane Transport Proteins; D009154:Mutation; D009994:Osmolar Concentration; D027981:Symporters
D026905:Amino Acid Transport Systems; D001426:Bacterial Proteins; D002352:Carrier Proteins; D003470:Culture Media; D029968:Escherichia coli Proteins; D050485:GABA Plasma Membrane Transport Proteins; C079244:ProP protein, E coli; C060774:ProU protein, Bacteria; D027981:Symporters; C072207:betaine plasma membrane transport proteins; D001622:Betaine