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M Futai

Publications and source records attributed to M Futai.

15 recordsLinked to original sources
PubMed1979

Specialized transducing phage lambda carrying the genes for coupling factor of oxidative phosphorylation of Escherichia coli: increased synthesis of coupling factor on induction of prophage lambda asn.

Studies were made of the synthesis of the coupling factor complex (F1--F0) of oxidative phosphorylation after prophage induction of a set of Escherichia coli strains lysogenic for defective transducing phage lambda asn, lambda uncA, or lambda bglC. The transducing phages had been isolated from a strain of E. coli carrying prophage lambda cI857 S7 within the bglB gene located near the unc gene cluster [Miki, T., Hiraga, S., Nagata, T. & Yura, T. (1978) Proc. Natl. Acad. Sci. USA 75, 5099--5103]. When lysogenic cells carrying lambda asn and lambda cI857 S7 were induced at high temperature, synthesis of the F1-ATPase portion of the complex increased to severalfold that of the noninduced cells. In contrast, no increase was observed upon thermoinduction of cells carrying lambda uncA or lambda bglC. The number of membrane sites that could bind purified F1-ATPase also increased significantly upon induction by lambda asn but not by lambda uncA or lambda bglC. In addition, F1-depleted membranes prepared from lambda asn-induced bacteria required more dicyclohexylcarbodiimide to seal the proton pathway than did those from noninduced bacteria. These results strongly suggest that lambda asn carries a set of bacterial genes coding for all the F1 polypeptides (the alpha, beta, gamma, delta, and probably the epsilon subunits) and at least some of the genes involved in formation of F0 polypeptides. Although lambda uncA carries the structural gene (uncA) for the alpha subunit of F1-ATPase, it apparently does not carry the whole set of F1--F0 genes.

Adenosine Triphosphatases↗
PubMed1978

Effects of phospholipids on L-lactate dehydrogenase from membranes of Escherichia coli. Activation and stabilization of the enzyme with phospholipids.

Membrane-bound L-lactate dehydrogenase was freed from the detergent used during purification. The detergent-free enzyme had about one-half the specific activity of the enzyme in 1.0% Tween 80, and was only partially sensitive to the specific antibody. This enzyme was activated about 3-fold with phosphatidylglycerol, cardiolipin, or a mixture of phospholipids. The phospholipid-activated enzyme had a similar Km value for L-lactate to that of the membrane enzyme and was completely inhibited by the specific antibody. On heat treatment, the phospholipid-activated enzyme was more stable than detergent-free enzyme and was as stable as membrane-bound enzyme. The alpha helical content of the enzyme increased 1.7-fold during preincubation with these lipids and the alpha helix became more stable during heat treatment than that of the detergent-free enzyme. These results suggest that the enzyme showed monomolecular dispersion in the lipid bilayer and that its conformation, including its active site and secondary structure, was different from that of the detergent-free enzyme. Phosphatidylethanolamine, dilauroyl lecithin and lecithin from egg yolk had none of the above effects on the activity or the secondary structure of the enzyme. On the other hand, mixtures of each of these lipids and cholate had essentially similar effects to phosphatidylglycerol.

Amino Acids↗
PubMed1978

Coupling factor ATPase from Escherichia coli. An uncA mutant (uncA401) with defective alpha subunit.

Inactive coupling factor ATPase (F1) was prepared from an uncoupled mutant (uncA401) of Escherichia coli. Reconstitution of ATPase activity was observed when alpha subunit from wild-type F1 was added to the dissociated inactive F1 and the mixture was dialyzed against buffer containing ATP and Mg2+. ATPase was also reconstituted when the mixture of alpha subunit (wild type) and crude extract from the mutant was dialyzed against the same buffer. These results indicate that the mutant is defective in alpha subunit, suggesting that the uncA401 locus carries the structural gene for alpha subunit, and that this polypeptide plays an essential role in ATPase activity in F1 molecule.

Adenosine Triphosphatases↗
PubMed1977

Studies on the turnovers in vivo of adenosine di- and triphosphates in a coupling factor of Escherichia coli.

The metabolic stabilities of bound adenine nucleotides in a membrane-bound ATPase (EF1) [EC 3.6.1.3] of Escherichia coli were studied by estimating their rates of turnover in vivo. Two-thirds of the bound ATP prelabelled with 32Pi in EF1 molecules was retained after 3 h in a chase medium. The bound ADP was chased rapidly with a half time of decrease of less than 1 h, the rate similar to that of cytoplasmic free nucleotides. These results suggest that bound ATP in the EF1 is not a direct intermediate in oxidative phosphorylation.

Adenosine Diphosphate↗
PubMed1976

Escherichia coli membrane D-lactate dehydrogenase. Isolation of the enzyme in aggregated from and its activation by Triton X-100 and phospholipids.

D-Lactate dehydrogenase was obtained in an aggregated form consisting of 2 to 3 molecules of the monomer enzyme after removal of most Triton X-100 from the preparation as described previously (1). The aggregate dissociated reversibly to the monomeric form after addition of 0.06% or 1.0% Triton X-100. Formation of these aggregates was confirmed by the finding that the enzyme activity was only partially sensitive to specific antibody. The specific activity of the aggregated enzyme was one-third that of the enzyme with Triton X-100 and it increased approximately 5-fold on addition of phospholipids or cardiolipin of Escherichia coli and lecithin from egg yolk. Both the monomer and micelle forms of Triton X-100 caused activation of the enzyme. The activity of the aggregates after preincubation with Triton X-100 or phospholipids was completely inhibited by specific antibody. The difference in the properties of the aggregated enzyme after preincubation with Triton X-100 and with phospholipids suggested that its interaction with phospholipids was stronger than with Triton X-100. Kinetic studies also suggested a difference between the interactions of the enzyme with phospholipids and with Triton X-100. Aggregated enzyme had an apparent Km value for D-lactate similar to that of membrane-bound enzyme after preincubation with phospholipids.

Cell Membrane↗
PubMed1975

Formation of phagolysosomes containing dextran and Triton WR 1339 in mouse liver.

After injection of Triton WR 1339 and dextran into mice, phagolysosomes containing both compounds were obtained from the liver regardless of the order of injection of these materials. This suggests that phagososomes containing the other material. The recoveries of various lysosomal enzymes differed in phagolysosomes after injection of Triton WR 1339 with or without dextran: recoveries of beta-glucuronidase, beta-N-acetylglucosaminidase and arylsulfatase were high, and that of acid phosphatase was low.

Acetylglucosamine↗
PubMed1975

Localization of D-lactate dehydrogenase in membrane vesicles prepared by using a french press or ethylenediaminetetraacetate-lysozyme from Escherichia coli.

The localization of D-lactate dehydrogenase in membrane vesicles prepared from Escherichia coli was studied using antibody against the purified enzyme. The activity of D-lactate dehydrogenase and D-lactate-dependent oxygen uptake of membrane vesicles prepared by using a French press were completely inhibited by this antibody, suggesting that the enzyme is localized on the outside of these vesicles. This and previous results (Futai, 1974) strongly indicate the inversion of these vesicles. The D-lactate dehydrogenase and D-lactate-dependent oxygen uptake of membrane vesicles prepared by treatment with ethylenediaminetetraacetate-lysozyme were inhibited about 15% by the antibody, whereas proline transport of the vesicles was insensitive to antibody. These results suggest that most of the membrane vesicles have D-lactate dehydrogenase on the inside of the membrane and that such vesicles transport amino acids. This essentially confirms the results of Short, Kaback, and Kohn (1975). However, unlike them we observed that a small but significant portion of activity was sensitive to the antibody as shown above. This portion may represent the completely inverted vesicles in the preparation. Ferricyanide reductase activity cannot be detected in spheroplasts, but about 30 to 50% of the total was detected in membrane vesicles prepared by treatment with ethylenediaminetetraacetate. This confirms our previous findings with membrane prepared by a slightly different procedure. It is concluded that in these vesicles about half the reactive sites for ferricyanide are moved from inside to outside the membrane, whereas 85% of the D-lactate dehydrogenase remains inside the membrane.

Antibodies, Bacterial↗