Comparative study of an adenosine triphosphatase trigger-fused lipid vesicle and other vesicle forms of dimyristoylphosphatidylcholine

Dufour, Jean Pierre; Nunnally, Ray L.; Buhle, Loren; Tsong, Tian Yow

doi:10.1021/bi00522a035

Cited by 25 publications

(15 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results presented show that the enzyme active site of lysozyme seems to be involved in a protein-induced fusion process. In contrast to the observations made when "fusogenic" proteins are used (27)(28)(29)(30)(31), lysozyme did not induce liposome-liposome fusion but showed fusogenic properties only when erythrocyte membranes were offered as a target and when it was covalently bound to the liposomes.…”

contrasting

confidence: 94%

Lysozyme-induced fusion of liposomes with erythrocyte ghosts at acidic pH.

Arvinte¹,

Hildenbrand²,

Wahl³

et al. 1986

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Lysozyme that was covalently bound to the outer surface of sonicated vesicles induced fusion of the vesicles with human white erythrocyte ghosts. The kinetics of membrane mixing were evaluated by the resonance-energy-transfer method using L-a-dipalmitoyl phosphatidylethanolamine labeled at the free amino group with the energy donor 7-nitro-2,1,3-benzoxadiazol-4-yl or with the energy acceptor tetramethylrhodamine. The equilibrium state after fusion was characterized by using fluorescence photobleaching and recovery techniques. Rates and equilibrium percentages of fusion were maximal at the pH optimum of the enzyme, and rates were strongly reduced by the addition of N,N',N"-triacetylchitotriose, a competitive inhibitor of lysozyme. An apparent activation energy of 28 ± kcal/mol was obtained for the lipid-mixing process. At 370C, the fusion half-time was 0.5 min. After 30 min at 370C, 40% of the labeled lipids initially present in the fusion mixture had a lateral diffusion constant, D, of 1.1 ± 0.5 x 10-9 cm2.sec-1 in the ghost membrane. The strong induction of fusion at the lysozyme pH optimum was not observed in the absence of lysozyme or when free lysozyme was added to the solution. Bound lysozyme did not induce fusion of electrically neutral liposomes with each other. These observations indicate that it is the liposome-bound lysozyme that induces fusion between liposomes and erythrocyte ghosts.

show abstract

contrasting

confidence: 94%

Lysozyme-induced fusion of liposomes with erythrocyte ghosts at acidic pH.

Arvinte¹,

Hildenbrand²,

Wahl³

et al. 1986

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…The first study reported that octyl glucoside dialyzed vesicles had a broadened main phase transition but otherwise nearly the same thermal properties as LMV (Petri et al, 1980). A second study reported that DMPC vesicles prepared by sodium deoxycholate partial solubilization and removal (Enoch & Strittmatter, 1979) had a main transition with a larger enthalpy, an increased half-width, and a higher phase transition temperature than found in the main transition of LMV (Dufour et al, 1981). A third report (Wong et al, 1982) stated that DPPC vesicles prepared by fusion of extremely concentrated SUV at low temperatures resulted in no change in the main transition temperature and essentially no change in peak width when compared to LMV (see Results and Table I).…”

Section: Discussionmentioning

confidence: 99%

“…It is concluded that LUV prepared by procedures that avoid impurities undergo a highly cooperative phase transition, as demonstrated here for fusion vesicles. (Milsmann et al, 1978;Enoch & Strittmatter, 1979; Zumbuehl & Weder, 1981; Petri et al, 1980;Mimms et al, 1981), and other procedures (Reeves & Dowben, 1969;Barenholz et al, 1979;Lichtenberg et al, 1981;Dufour et al, 1981). While advantageous for some applications, these preparations suffer from several shortcomings.…”

mentioning

confidence: 99%

Phase behavior of large unilamellar vesicles composed of synthetic phospholipids

Parente¹,

Lentz

1984

Biochemistry

View full text Add to dashboard Cite

Large unilamellar vesicles (LUV) have been prepared by three procedures from several synthetic and natural phosphatidylcholines. Reverse-phase evaporation vesicles (REV) and fusion vesicles were prepared by established procedures. A published procedure for the preparation of dialyzed octyl glucoside vesicles (DOV) was modified to allow its use with synthetic phospholipids. Negative-staining and freeze--fracture electron microscopy was used to determine the vesicle size distribution (mean diameters 800-1000 A) and extent of oligolamellar contamination in DOV preparations. Trapping of 6-carboxyfluorescein yielded measurements of the internal volume (2.6 +/- 0.3 microL/mumol of Pi) consistent with the size distributions determined by electron microscopy. An upper limit of less than 3 mol % oligolamellar vesicle contamination was indicated by calorimetric heat capacity profiles. The phase behaviors of large multilamellar vesicles and all three types of LUV were compared by using high-sensitivity differential scanning calorimetry and fluorescence depolarization of the membrane probe diphenylhexatriene. The most remarkable feature was the increased breadth of the main transition of DOV and of REV relative to the multilamellar species and to fusion vesicles. Both the main transition and the pretransition occurred at nearly the same temperatures in unilamellar and multilamellar species, but the unilamellar pretransition involved less than half the enthalpy observed in the multilamellar transition. Additional experiments indicated that the broadened main phase transition associated with DOV and REV reflected bilayer impurities resulting from preparation. It is concluded that LUV prepared by procedures that avoid impurities undergo a highly cooperative phase transition, as demonstrated here for fusion vesicles.

show abstract

“…below the phase transition temperature of the phospholipid triggers a formation of unilamellar macrovesicles (95-nm mean Diam). Studies of this fusion process together with characterization of the enzyme in these micro-and macrovesicles allow us to assess the effect of lipid structures on the enzyme-substrate interactions (5,6).…”

Section: Resultsmentioning

confidence: 99%

“…Proton influx was monitored following quenching of a fluorescent acridine dye (9-amino-6-chloro-2-methoxy-acridine). The assay medium contained in a final volume of 1.5 ml at pH 6.0 and 300C, 6 mM MgATP (Sigma Chemical Corp., St. Louis, MO), 10 mM MES/Tris, 300 mM KC1, 1.6 MM acridine dye and 4.3 mg phospholipid vesicles containing 6.6 Mtg of protein. All assay components except acridine dye and MgATP were added first and allowed to incubate for 4 min.…”

Section: Resultsmentioning

confidence: 99%