Factors defining the functional coupling of bacteriorhodopsin and ATP synthase in liposomes

Bend, R L van der; Cornelissen, J.B.W.J.; Berden, J.A.; Dam, K. Van

doi:10.1016/0005-2728(84)90082-3

Cited by 30 publications

(18 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This value is comparable to that observed in a variety of co-reconstituted preparations (8)(9)(10)(11)(12). Recently, van der Bend et al (13) reported synthetic rates of up to 500 nmol-mg-l min-' with co-reconstituted preparations of the mitochondrial ATP synthase. In the present study, we report the co-reconstitution of bR and DSA from spinach chloroplasts with maximum rates of light-driven ATP synthesis of -1 ,umol-mg-1-min-.…”

supporting

confidence: 78%

“…Sci. USA 83 (1986) vesicles, whereas a 4.2-fold stimulation was observed in phosphatidylcholine vesicles (13). Despite the apparent increase in the leakiness of the asolectin vesicles, the observed synthetic activity was still superior to that found in the phosphatidyl choline vesicles (13).…”

Section: Resultsmentioning

confidence: 86%

“…The rate is a factor of 2 larger than the best coreconstituted preparation of bR and the mitochondrial ATP synthase (13). However, the estimated rate of ATP synthesis in oxidative phosphorylation (13) is a factor of 5 larger, and the maximum levels of photophosphorylation estimated in chloroplasts are 50 times larger (22).…”

Section: Resultsmentioning

confidence: 92%

See 2 more Smart Citations

Steady-state ATP synthesis by bacteriorhodopsin and chloroplast coupling factor co-reconstituted into asolectin vesicles.

Krupinski¹,

Hammes²

1986

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

View full text Add to dashboard Cite

A method was developed for the co-reconstitution of bacteriorhodopsin and chloroplast coupling factor in asolectin vesicles. First, bacteriorhodopsin was reconstituted from a mixture of octyl glucoside, asolectin, and protein in the presence of ethylenediaminetetraacetic acid by passage through a Sephadex G-50 centrifuge column. Then, the purified coupling factor was reconstituted from a mixture ofsodium cholate, bacteriorhodopsin vesicles, and coupling factor in the presence of Mg2' by passage through the centrifuge column.Sucrose density-gradient centrifugation indicated a band of vesicles with slightly different positions in the gradient for maximum vesicle concentration, bacteriorhodopsin vesicle concentration, ATP synthesis, and ATP hydrolysis. The rate of light-driven ATP synthesis reaches a limiting value as the concentration of bacteriorhodopsin and the light intensity are increased. A steady-state rate of ATP synthesis of 1 Ismol per mg of coupling factor-min has been achieved. Apparently this rate is limited by the heterogeneity within the vesicle population and by the ability of bacteriorhodopsin to form a sufficiently large pH gradient.Bacteriorhodopsin (bR) is a light-driven proton pump found in the purple membrane of Halobacterium halobium (cf. ref. 1). It is readily reconstituted into phospholipid vesicles in which the interior is acidified upon illumination (cf. ref. 2). Racker and Stoeckenius (3) were the first to demonstrate that vesicles co-reconstituted with bR and the ATP synthesizing complex, initially from mitochondria, synthesized ATP from ADP and inorganic phosphate upon illumination of the vesicles. The observed rates of ATP synthesis were -0.1% of the rates for oxidative phosphorylation found in mitochondria. A highly active co-reconstituted preparation of bR and ATP synthase would be an ideal model system with which to perform studies on the mechanism of energy coupling. Consequently, this experimental system has been refined and applied to other ATPases.The dicyclohexylcarbodiimide-sensitive ATP-synthesizing complex from chloroplasts (DSA) (cf. ref. 4) was first successfully co-reconstituted with bR by Winget et al. (5). Subsequently, the co-reconstituted system was used to study the steady-state kinetics of ATP synthesis and hydrolysis (6,7). The maximum level of light-dependent ATP synthesis in those studies was -100 nmol-mg-1 min-1. This value is comparable to that observed in a variety of co-reconstituted preparations (8-12). Recently, van der Bend et al. (13) reported synthetic rates of up to 500 nmol-mg-l min-' with co-reconstituted preparations of the mitochondrial ATP synthase. In the present study, we report the co-reconstitution of bR and DSA from spinach chloroplasts with maximum rates of light-driven ATP synthesis of -1 ,umol-mg-1-min-. MATERIALS AND METHODSChemicals. Asolectin was from Associated Concentrates (Woodside, NY). Sephadex G-50 fine was from Pharmacia Fine Chemicals. Pyranine was from Molecular Probes (Plano, TX). Octyl B-D-glucopyranoside was from Ca...

show abstract

supporting

confidence: 78%

Section: Resultsmentioning

confidence: 86%

See 1 more Smart Citation

Steady-state ATP synthesis by bacteriorhodopsin and chloroplast coupling factor co-reconstituted into asolectin vesicles.

Krupinski¹,

Hammes²

1986

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

View full text Add to dashboard Cite

show abstract

“…The pellet was resuspended in 100 l of buffer containing 500 mM mannitol, 1 mM ATP, 2 mM EDTA, 0.2% (wt/vol) bovine serum albumin, 10% methanol, and 10 mM ε-aminocaproic acid in 0.1 M Tris-HCl (pH 7.5) and then extracted by vigorous shaking for 30 min with 0.2-g glass beads (diameter of ca. 0.45 ϫ 10 Ϫ3 m) at 4°C (42). To inhibit protease activity, 1 M PMSF (in DMSO) was added.…”

Section: Methodsmentioning

confidence: 99%

“…Mitochondrial ATPase activity (azide-sensitive ATP hydrolysis) was determined by subtracting the azide-insensitive ATPase activity from the total ATPase activity. Total ATPase activity was measured at 30°C at pH 8.0 with 0.5 mM phosphoenolpyruvate, 6 mM MgCl 2 ⅐ 6H 2 O, 85 mM sucrose, 5 mM ATP, 35 mM Tris-HCl, 0.3 mM NADH, 50 M antimycin A, 5 U of pyruvate kinase per ml, and 5 U of lactate dehydrogenase per ml (42). The reaction was started with crude enzyme extract.…”

Section: Methodsmentioning

confidence: 99%

Physiological Properties of Saccharomyces cerevisiae from Which Hexokinase II Has Been Deleted

Diderich

Raamsdonk

Kruckeberg

et al. 2001

Appl Environ Microbiol

View full text Add to dashboard Cite

Hexokinase II is an enzyme central to glucose metabolism and glucose repression in the yeast Saccharomyces cerevisiae. Deletion of HXK2, the gene which encodes hexokinase II, dramatically changed the physiology of S. cerevisiae. The hxk2-null mutant strain displayed fully oxidative growth at high glucose concentrations in early exponential batch cultures, resulting in an initial absence of fermentative products such as ethanol, a postponed and shortened diauxic shift, and higher biomass yields. Several intracellular changes were associated with the deletion of hexokinase II. The hxk2 mutant had a higher mitochondrial H ؉ -ATPase activity and a lower pyruvate decarboxylase activity, which coincided with an intracellular accumulation of pyruvate in the hxk2 mutant. The concentrations of adenine nucleotides, glucose-6-phosphate, and fructose-6-phosphate are comparable in the wild type and the hxk2 mutant. In contrast, the concentration of fructose-1,6-bisphosphate, an allosteric activator of pyruvate kinase, is clearly lower in the hxk2 mutant than in the wild type. The results suggest a redirection of carbon flux in the hxk2 mutant to the production of biomass as a consequence of reduced glucose repression.

show abstract

Phospholipid Membranes as Chemically and Functionally Tunable Materials

Huster,

Maiti,

Herrmann

2024

Advanced Materials

View full text Add to dashboard Cite

The sheet‐like lipid bilayer is the fundamental structural component of all cell membranes. Its building blocks are phospholipids and cholesterol. Their amphiphilic structure spontaneously leads to the formation of a bilayer in aqueous environment. Lipids are not just structural elements. Individual lipid species, the lipid membrane structure, and lipid dynamics influence and regulate membrane protein function. An exciting field is emerging where the membrane‐associated material properties of different bilayer systems are used in designing innovative solutions for widespread applications across various fields, such as the food industry, cosmetics, nano‐ and biomedicine, drug storage and delivery, biotechnology, nano‐ and biosensors, and computing. Here, the authors summarize what is known about how lipids determine the properties and functions of biological membranes and how this has been or can be translated into innovative applications. Based on recent progress in the understanding of membrane structure, dynamics, and physical properties, a perspective is provided on how membrane‐controlled regulation of protein functions can extend current applications and even offer new applications.

show abstract

Factors defining the functional coupling of bacteriorhodopsin and ATP synthase in liposomes

Cited by 30 publications

References 33 publications

Steady-state ATP synthesis by bacteriorhodopsin and chloroplast coupling factor co-reconstituted into asolectin vesicles.

Steady-state ATP synthesis by bacteriorhodopsin and chloroplast coupling factor co-reconstituted into asolectin vesicles.

Physiological Properties of Saccharomyces cerevisiae from Which Hexokinase II Has Been Deleted

Phospholipid Membranes as Chemically and Functionally Tunable Materials

Contact Info

Product

Resources

About