1
|
Protonated dye-surfactant ion pair formation between neutral red and anionic surfactants in aqueous submicellar solutions. J Mol Liq 2008. [DOI: 10.1016/j.molliq.2008.05.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
2
|
Junge W, Haumann M, Ahlbrink R, Mulkidjanian A, Clausen J. Electrostatics and proton transfer in photosynthetic water oxidation. Philos Trans R Soc Lond B Biol Sci 2002; 357:1407-17; discussion 1417-20. [PMID: 12437879 PMCID: PMC1693046 DOI: 10.1098/rstb.2002.1137] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Photosystem II (PSII) oxidizes two water molecules to yield dioxygen plus four protons. Dioxygen is released during the last out of four sequential oxidation steps of the catalytic centre (S(0) --> S(1), S(1) --> S(2), S(2) --> S(3), S(3) --> S(4) --> S(0)). The release of the chemically produced protons is blurred by transient, highly variable and electrostatically triggered proton transfer at the periphery (Bohr effect). The extent of the latter transiently amounts to more than one H(+)/e(-) under certain conditions and this is understood in terms of electrostatics. By kinetic analyses of electron-proton transfer and electrochromism, we discriminated between Bohr-effect and chemically produced protons and arrived at a distribution of the latter over the oxidation steps of 1 : 0 : 1 : 2. During the oxidation of tyr-161 on subunit D1 (Y(Z)), its phenolic proton is not normally released into the bulk. Instead, it is shared with and confined in a hydrogen-bonded cluster. This notion is difficult to reconcile with proposed mechanisms where Y(Z) acts as a hydrogen acceptor for bound water. Only in manganese (Mn) depleted PSII is the proton released into the bulk and this changes the rate of electron transfer between Y(Z) and the primary donor of PSII P(+)(680) from electron to proton controlled. D1-His190, the proposed centre of the hydrogen-bonded cluster around Y(Z), is probably further remote from Y(Z) than previously thought, because substitution of D1-Glu189, its direct neighbour, by Gln, Arg or Lys is without effect on the electron transfer from Y(Z) to P(+)(680) (in nanoseconds) and from the Mn cluster to Y(ox)(Z).
Collapse
Affiliation(s)
- Wolfgang Junge
- Abteilung Biophysik, Universität Osnabrück, D-49069 Osnabrück, Germany.
| | | | | | | | | |
Collapse
|
3
|
Geimonen E, Batrukova MA, Rubtsov AM. Thermal uncoupling of the Ca(2+)-transporting ATPase in sarcoplasmic reticulum. Changes in surface properties of light vesicles. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 225:347-54. [PMID: 7925455 DOI: 10.1111/j.1432-1033.1994.00347.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
It is known that the light fraction of rabbit skeletal muscle sarcoplasmic reticulum vesicles can release Ca2+ from the intravesicular space, although the Ca(2+)-conductive channels are present only in the heavy fraction of sarcoplasmic reticulum vesicles. To study the possible pathways of the Ca2+ leakage from light vesicles we have used a short-term treatment for 4.5 min at 45 degrees C which quickly decreases the efficiency of Ca(2+)-transporting ATPase operation without any visible effects on the hydrolytic activity of the Ca(2+)-ATPase in the membranes. The treatment of the vesicles decreased the negative membrane surface potential created by the Ca(2+)-ATPase. Comparative titration of control and heat-treated preparations of light sarcoplasmic reticulum vesicles by K+, Na+, Mg2+, and Ca2+ revealed clear differences in their surface properties. The short-term heating resulted in release of Ca2+ from the vesicles previously loaded with 45Ca2+, which indicates an increase in passive membrane permeability to Ca2+. Study of Ca(2+)-ATPase protein arrangement in the membrane indicated that the heat treatment induced protein oligomerization and some of the Ca(2+)-ATPase molecules acquired intermolecular and intramolecular covalent bonds. From these data, we have concluded that the changes in the surface and structure properties of the vesicle membranes after the short-term heat treatment were the result of clustering of the Ca(2+)-ATPase molecules. This protein rearrangement may create channels for calcium leakage from light sarcoplasmic reticulum vesicles.
Collapse
Affiliation(s)
- E Geimonen
- Department of Biochemistry and Biophysics, Institute of Experimental Biology of the Estonian Academy of Sciences, Harku
| | | | | |
Collapse
|
4
|
Groth G, Junge W. Proton slip of the chloroplast ATPase: its nucleotide dependence, energetic threshold, and relation to an alternating site mechanism of catalysis. Biochemistry 1993; 32:8103-11. [PMID: 8394125 DOI: 10.1021/bi00083a008] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The F-ATPase of chloroplasts couples proton flow to ATP synthesis, but is leaky to protons in the absence of nucleotides. This "proton slip" can be blocked by small concentrations of ADP or by inhibitors of the channel portion, CF0. We studied charge flow through the ATPase by flash spectrophotometry and analyzed the inhibition of proton slip by nucleotides, phosphate/arsenate, and insufficient proton motive force. The following inhibition constants (at given background concentrations) were observed: ADP, 0.2 microM (0.5 mM P(i)); ADP, 13.4 microM (no P(i)); P(i), 43 microM (1 microM ADP); GDP, 2.5 microM (0.5 mM P(i)); ATP, 2 microM. ADP and P(i) mutually lowered their respective inhibition constants. Phosphate could be replaced by arsenate. Proton slip occurred only if the proton motive force exceeded a certain threshold, similar to that for ATP synthesis. The inhibition of proton slip by ADP and GDP qualified the respective nucleotide binding sites as belonging to the subset of two (or three) potentially catalytic sites out of the total of six. We interpreted the ADP-induced transition between different conduction states of the ATPase from "slipping" to "closed" to "coupled" as a consequence of the alternating site mechanism of catalysis. Whereas the proton translocator idles in the absence of nucleotides, the high-affinity binding of the first ADP/P(i) couple to one site clutches proton flow to some (conformational) change that can only be executed after the binding of another ADP/P(i) couple to a second site. From there on these sites alternate in the catalytic cycle. An entropic machine is presented which likewise models proton slip, unisite, and multisite ATP synthesis and hydrolysis.
Collapse
Affiliation(s)
- G Groth
- Universität Osnabrück, Germany
| | | |
Collapse
|
5
|
Maróti P. Flash-induced proton transfer in photosynthetic bacteria. PHOTOSYNTHESIS RESEARCH 1993; 37:1-17. [PMID: 24317650 DOI: 10.1007/bf02185435] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/1992] [Accepted: 03/27/1993] [Indexed: 06/02/2023]
Abstract
A proton electrochemical potential across the membranes of photosynthetic purple bacteria is established by a light-driven proton pump mechanism: the absorbed light in the reaction center initiates electron transfer which is coupled to the vectorial displacement of protons from the cytoplasm to the periplasm. The stoichiometry and kinetics of proton binding and release can be tracked directly by electric (glass electrodes), spectrophotometric (pH indicator dyes) and conductimetric techniques. The primary step in the formation of the transmembrane chemiosmotic potential is the uptake of two protons by the doubly reduced secondary quinone in the reaction center and the subsequent exchange of hydroquinol for quinone from the membrane quinone-pool. However, the proton binding associated with singly reduced promary and/or secondary quinones of the reaction center is substoichiometric, pH-dependent and its rate is electrostatically enhanced but not diffusion limited. Molecular details of protonation are discussed based on the crystallographic structure of the reaction center of purple bacteriaRb. sphaeroides andRps. viridis, structure-based molecular (electrostatic) calculations and mutagenesis directed at protonatable amino acids supposed to be involved in proton conduction pathways.
Collapse
Affiliation(s)
- P Maróti
- Institute of Biophysics, József Attila University Szeged, Egyetem utca 2, H-6722, Szeged, Hungary
| |
Collapse
|
6
|
Thylakoid lumenal pH determination using a fluorescent dye: Correlation of lumen pH and gating between localized and delocalized energy coupling. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1993. [DOI: 10.1016/0005-2728(93)90156-a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
7
|
Gilmore AM, Yamamoto HY. Linear models relating xanthophylls and lumen acidity to non-photochemical fluorescence quenching. Evidence that antheraxanthin explains zeaxanthin-independent quenching. PHOTOSYNTHESIS RESEARCH 1993; 35:67-78. [PMID: 24318621 DOI: 10.1007/bf02185412] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/1992] [Accepted: 07/27/1992] [Indexed: 05/09/2023]
Abstract
Zeaxanthin has been correlated with high-energy non-photochemical fluorescence quenching but whether antheraxanthin, the intermediate in the pathway from violaxanthin to zeaxanthin, also relates to quenching is unknown. The relationships of zeaxanthin, antheraxanthin and ΔpH to fluorescence quenching were examined in chloroplasts ofPisum sativum L. cv. Oregon andLactuca sativa L. cv. Romaine. Data matrices as five levels of violaxanthin de-epoxidation against five levels of light-induced lumen-proton concentrations were obtained for both species. The matrices included high levels of antheraxanthin as well as lumen-proton concentrations induced by subsaturating to saturation light levels. Analyses of the matrices by simple linear and multiple regression showed that quenching is predicted by models where the major independent variable is the product of lumen acidity and de-epoxidized xanthophylls, the latter as the sum of zeaxanthin and antheraxanthin. The interactions of lumen acidity and xanthophyll concentration are shown in three-dimensional plots of the best-fit multiple regression models. Antheraxanthin apparently contributes to quenching as effectively as zeaxanthin and explains quenching previously not accounted for by zeaxanthin. Hence, we propose that all high-energy dependent quenching is xanthophyll dependent. Quenching requires a threshold lumen pH that varies with xanthophyll composition. After the threshold, quenching is linear with lumen acidity or xanthophyll composition.
Collapse
Affiliation(s)
- A M Gilmore
- Department of Plant Molecular Physiology, University of Hawaii at Manoa, 3190 Maile Way, St. John 503, 96822, Honolulu, Hawaii, USA
| | | |
Collapse
|
8
|
Lavergne J, Junge W. Proton release during the redox cycle of the water oxidase. PHOTOSYNTHESIS RESEARCH 1993; 38:279-296. [PMID: 24317981 DOI: 10.1007/bf00046752] [Citation(s) in RCA: 108] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/1993] [Accepted: 10/01/1993] [Indexed: 05/28/2023]
Abstract
Old and very recent experiments on the extent and the rate of proton release during the four reaction steps of photosynthetic water oxidation are reviewed. Proton release is discussed in terms of three main sources, namely the chemical production upon electron abstraction from water, protolytic reactions of Mn-ligands (e.g. oxo-bridges), and electrostatic response of neighboring amino acids. The extent of proton release differs between the four oxidation steps and greatly varies as a function of pH both, but differently, in thylakoids and PS II-membranes. Contrastingly, it is about constant in PS II-core particles. In any preparation, and on most if not all reaction steps, a large portion of proton transfer can occur very rapidly (<20 μs) and before the oxidation of the Mn-cluster by Yz (+) is completed. By these electrostatically driven reactions the catalytic center accumulates bases. An additional slow phase is observed during the oxygen evolving step, S3⇒S4→S0. Depending on pH, this phase consists of a release or an uptake of protons which accounts for the balance between the number of preformed bases and the four chemically produced protons. These data are compatible with the hypothesis of concerted electron/proton-transfer to overcome the kinetic and energetic constraints of water oxidation.
Collapse
Affiliation(s)
- J Lavergne
- Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005, Paris, France
| | | |
Collapse
|
9
|
Luvisetto S, Schmehl I, Cola C, Azzone GF. Tracking of proton flow during transition from anaerobiosis to steady state. 1. Response of matrix pH indicators. EUROPEAN JOURNAL OF BIOCHEMISTRY 1991; 202:113-20. [PMID: 1657603 DOI: 10.1111/j.1432-1033.1991.tb16351.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
1. The kinetics of acidification and realkalinization of the matrix after addition of nigericin to respiring and non-respiring mitochondria, recorded by intramitochondrial pH indicators such as neutral red and 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF), is complementary to that recorded by extramitochondrial pH indicators. The extent of acidification decreases with the logarithm of the KCl concentration and is inhibited by Pi and ammonium ions. 2. Proton translocation during respiration has been compared with proton extraction from matrix bulk water. During oxygen pulses to EGTA-untreated mitochondria, BCECF records an extraction of protons from matrix bulk water of about 2-3 nmol H+/mg, reduced to 1-2 nmol H+/mg in EGTA-treated mitochondria. Since the amount of proton translocation required to achieve steady state is of the order of 6-7 nmol H+/mg, it appears that 75-90% of the protons are not extracted from matrix bulk water. Only a slight response is recorded by neutral red. 3. The effect of permeant cations and of uncouplers on the distribution of proton extraction between membrane and matrix bulk water has been studied in presteady state. During Sr2+ uptake, proton extrusion into cytosolic bulk water, as well as proton extraction from matrix bulk water, corresponds almost to 100% of the protons translocated by the redox proton pumps. In the absence of Sr2+, parallel to the disappearance of the proton extrusion in cytosolic bulk water, the proton extraction from matrix bulk water diminishes to about 20% of the proton translocation. 4. The mechanism by which divalent cation uptake and protonophoric uncouplers affect the distribution of proton extraction between matrix bulk water and membrane domains and the nature of the membrane domains are discussed.
Collapse
Affiliation(s)
- S Luvisetto
- C.N.R. Unit for the Study of Physiology of Mitochondria, University of Padova, Italy
| | | | | | | |
Collapse
|
10
|
Stoichiometry of proton release during photosynthetic water oxidation: a reinterpretation of the responses of Neutral red leads to a non-integer pattern. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1991. [DOI: 10.1016/s0005-2728(05)80142-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
11
|
Hope A, Rich P. Proton uptake by the chloroplast cytochrome bf complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1989. [DOI: 10.1016/s0005-2728(89)80206-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
12
|
Schroeder C, Heider H, Eggers HJ. Neutral red-labeled influenza virus loses photosensitivity during absorption to host cells but not to erythrocytes. Arch Virol 1989; 108:81-8. [PMID: 2596976 DOI: 10.1007/bf01313745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Neutral red (NR)-labeled influenza virus is extremely photosensitive. Unlike NR-labeled picornaviruses which lose their photosensitivity only after penetrating the host cell, NR-labeled influenza virus loses most of its photosensitivity during adsorption at 4 degrees C. We demonstrate that the underlying reaction occurs within seconds of adsorption and that it is irreversible, i.e., NR virus eluted from chick embryo cells after adsorption is hardly photosensitive anymore. In contrast to this, NR virus adsorbed to and eluted from erythrocytes retains its original photosensitivity. We suggest that the loss of photosensitivity during adsorption of NR virus to host cells reflects a conformational change in the virion which is not elicited by adsorption to red blood cells.
Collapse
Affiliation(s)
- C Schroeder
- Institut für Virologie, Bereich Medizin (Charité), Humboldt-Universität zu Berlin, German Democratic Republic
| | | | | |
Collapse
|
13
|
Rottenberg H. Proton electrochemical potential gradient in vesicles, organelles, and prokaryotic cells. Methods Enzymol 1989; 172:63-84. [PMID: 2747544 DOI: 10.1016/s0076-6879(89)72008-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|
14
|
|
15
|
Wille B. Thylakoid volume, proton translocation and buffering capacity as measured with spin-label techniques. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1988. [DOI: 10.1016/0005-2728(88)90028-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|