Lipid requirement of the branched-chain amino acid transport system of Streptococcus cremoris

• Published in: Biochemistry (Easton) 1988-02, Vol.27 (3), p.865-872
• Main Authors: Driessen, Arnold J. M, Zheng, Tan, In't Veld, Gerda, Op den Kamp, Jos A. F, Konings, Wil N
• Format: Article
• Language: English
• Subjects: ACIDE GRAS; ACIDOS GRASOS; amino acids; Amino Acids, Branched-Chain - metabolism; Biological and medical sciences; Biological Transport; Cardiolipins - isolation & purification; Cardiolipins - metabolism; Cell Membrane - metabolism; Cell physiology; CONTENIDO DE LIPIDOS; Escherichia coli - metabolism; FATTY ACIDS; Fundamental and applied biological sciences. Psychology; Glycolipids - isolation & purification; Glycolipids - metabolism; Kinetics; LIPID CONTENT; lipids; Liposomes; Membrane and intracellular transports; Membrane Lipids - metabolism; Molecular and cellular biology; Phosphatidylglycerols - isolation & purification; Phosphatidylglycerols - metabolism; STREPTOCOCCUS; Streptococcus - metabolism; Streptococcus cremoris; TENEUR EN LIPIDES
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi00403a005

The role of the membrane lipid composition on the transport protein of branched-chain amino acids of the homofermentative lactic acid bacterium Streptococcus cremoris has been investigated. The major membrane lipid species identified in S. cremoris were acidic phospholipids (phosphatidylglycerol and cardiolipin), glycolipids, and glycerophosphoglycolipids. Phosphatidylethanolamine (PE) was completely absent. Protonmotive force-driven and counterflow transport of leucine was assayed in fused membranes of S. cremoris membrane vesicles and liposomes composed of different lipids obtained by the freeze/thaw-sonication technique. High transport activities were observed with natural S. cremoris and Escherichia coli lipids, as well as with mixtures of phosphatidylcholine (PC) with PE or phosphatidylserine. High transport activities were also observed with mixtures of PC with monogalactosyl diglyceride, digalactosyl diglyceride, or a neutral glycolipid fraction isolated from S. cremoris. PC or mixtures of PC with phosphatidylglycerol, phosphatidic acid, or cardiolipin showed low activities. In mixtures of PC and methylated derivatives of PE, both counterflow and protonmotive force-driven transport activities decreased with increasing degree of methylation of PE. The decreased transport activity in membranes containing PC could be restored by refusion with PE-containing liposomes. These results demonstrate that both aminophospholipids and glycolipids can be activators of the leucine transport system from S. cremoris. It is proposed that aminophospholipids in Gram-negative bacteria and glycolipids in Gram-positive bacteria have similar functions with respect to solute transport.