Proton-linked L-fucose transport in Escherichia coli.
1. Addition of L-fucose to energy-depleted anaerobic suspensions of Escherichia coli elicited an uncoupler-sensitive alkaline pH change diagnostic of L-fucose/H+ symport activity. 2. L-Galactose or D-arabinose were also substrates, but not inducers, for the L-fucose/H+ symporter. 3. L-Fucose transport into subcellular vesicles was dependent upon respiration, displayed a pH optimum of about 5.5, and was inhibited by protonophores and ionophores. 4. These results showed that L-fucose transport into E. coli was energized by the transmembrane electrochemical gradient of protons. 5. Neither steady state kinetic measurements nor assays of L-fucose binding to periplasmic proteins revealed the existence of a second L-fucose transport system.
Bradley
S A
SA
Department of Biochemistry, University of Cambridge, U.K.
Tinsley
C R
CR
Muiry
J A
JA
Henderson
P J
PJ
D000963:Antimetabolites / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D050260:Carbohydrate Metabolism; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism*; D005643:Fucose / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011522:Protons; D013347:Subcellular Fractions / Q000378:metabolism; D013379:Substrate Specificity
D000963:Antimetabolites; D011522:Protons; D005643:Fucose