Orientation of the porphyrin ring in artificial chlorophyll membranes

Steinemann, A.; Stark, G.; Läuger, P.

doi:10.1007/bf01868051

Cited by 48 publications

(9 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An exception is the work of Yguerabide and Stryer (1971), who showed that fluorescence spectroscopy of macroscopic bilayer vesicles (1-4 mm diameter) was possible. Other spectroscopic studies have been done in special cases where chromophores (e.g., chlorophyll) are in' corporated in the BLM (black lipid membrane) (e.g., Cherry, Hsu & Chapman, 1972;Steinemann, Stark & L~iuger, 1972). For the most part, however, indirect methods must be used.…”

Section: Discussionmentioning

confidence: 98%

Voltage jump/capacitance relaxation studies of bilayer structure and dynamics

Sargent

1975

J. Membrain Biol.

View full text Add to dashboard Cite

Summary.A voltage-jump technique for the study of the time course of small, voltageinduced changes in the structure of single bilayers is presented, and a method is introduced whereby electromechanical (electrostrictive) phenomena can be separated from dielectric relaxations. As no foreign molecules need be introduced into the bilayers, the question about probe artifacts is eliminated individual dipoles about an axis lying in the plane of the membrane. Electrostictive effects with time constants between about 2 and 50 msec were also detected. A temperature study of both the dielectric and elect rostrictive phenomena is reported. The application of the technique to other membrane compositions and to a variety of BLM problems is discussed.

show abstract

Section: Discussionmentioning

confidence: 98%

Voltage jump/capacitance relaxation studies of bilayer structure and dynamics

Sargent

1975

J. Membrain Biol.

View full text Add to dashboard Cite

show abstract

“…l,,,, I,,, being direction cosines relating the direction of the molecular axis i j with the laboratory axis of rotation, and the angled brackets denote averages over all molecules in the light path. However, since the orientation of the pigment is due to the incorporation of the phytyl chain into the GMO lamellae (see Discussion, and also Steinemann et al, 1972), in the molecule-fixed coordinate system chosen above the orientation parameter matrix is diagonal:…”

Section: Treatment Of Datamentioning

confidence: 99%

LINEAR DICHROISM(250–700 nm) OF CHLOROPHYLL a AND PHEOPHYTIN a ORIENTED IN A LAMELLAR PHASE OF GLYCERYLMONOOCTANOATE/H₂O. CHARACTERIZATION OF ELECTRONIC TRANSITIONS

Fragata

Nordén

Kurucsev

1988

Photochem & Photobiology

120

View full text Add to dashboard Cite

Abstract— We determined the polarized and isotropic visible/UV absorption spectra of chlorophyll a (Chi a) and pheophytin a (Pheo a) oriented in the lamellar phase of glycerylmonooctanoate/H2O. Resolution into mutually perpendicular X‐ and Y‐polarized absorption spectra of the pigments was achieved assuming that the transition moments of Chi a and Pheo a are located in the plane of the chromophores. The polarized spectra were deconvoluted into harmonic progressions and the resultant assignment of band positions in the long‐wavelength region was found to correlate well with independent spectral measurements, such as the polarisation of fluorescence. However, the correlation of the experimentally determined transitions with the results of theoretical calculations is not straightforward. The overall conclusions are of fundamental interest in the determination of orientations of the tetrapyrrole macrocycle in lipid lamellae and pigment‐protein structures of photosynthetic membranes.

show abstract

“…Therefore, at small light intensities (outside the saturation region) the photocurrent should be proportional to cos 2 ~p. Assuming that the purple-membrane sheets have no preferential orientation within the plane of the bilayer, the calculation of cos 2 ~ leads to the following expression for the photocurrent I (Steinemann et al, 1972): …”

Section: Polarization Effectsmentioning

confidence: 99%

Photocurrents generated by bacteriorhodopsin on planar bilayer membranes

Bamberg

Apell

Dencher

et al. 1979

Biophys. Struct. Mechanism

Self Cite

142

111

View full text Add to dashboard Cite

Abstract. When purple-membrane fragments from Halobacterium halobium are added to one aqueous phase of a positively-charged black lipid membrane, the membrane becomes photoelectrically active. Under normal conditions the steady-state photo-current is extremely low, but increases considerably when the lipid bilayer is doped with proton-permeable gramicidin channels or with a lipophilic acid-base system. These findings indicate that the purple-membrane sheets are bound to the surface of the bilayer, forming a sandwich-like structure. The time-behaviour of the photocurrent may be interpreted on the basis of a simple equivalent circuit which contains the conductance and capacitance of the purple membrane in series with the conductance and capacitance of the lipid bilayer. From the dependence of the photocurrent on the polarization of the exciting light the average angle between the transition moment of the retinal chromophore and the plane of the bilayer was calculated to be about 28 degrees. Furthermore, it was shown that chromophore-free apomembrane binds to the lipid bilayer and that its photoelectrical activity can be restored in situ by adding all-trans-retinal to the aqueous phase.

show abstract

Orientation of the porphyrin ring in artificial chlorophyll membranes

Cited by 48 publications

References 23 publications

Voltage jump/capacitance relaxation studies of bilayer structure and dynamics

Voltage jump/capacitance relaxation studies of bilayer structure and dynamics

LINEAR DICHROISM(250–700 nm) OF CHLOROPHYLL a AND PHEOPHYTIN a ORIENTED IN A LAMELLAR PHASE OF GLYCERYLMONOOCTANOATE/H₂O. CHARACTERIZATION OF ELECTRONIC TRANSITIONS

Photocurrents generated by bacteriorhodopsin on planar bilayer membranes

Contact Info

Product

Resources

About

Orientation of the porphyrin ring in artificial chlorophyll membranes

Cited by 48 publications

References 23 publications

Voltage jump/capacitance relaxation studies of bilayer structure and dynamics

Voltage jump/capacitance relaxation studies of bilayer structure and dynamics

LINEAR DICHROISM(250–700 nm) OF CHLOROPHYLL a AND PHEOPHYTIN a ORIENTED IN A LAMELLAR PHASE OF GLYCERYLMONOOCTANOATE/H2O. CHARACTERIZATION OF ELECTRONIC TRANSITIONS

Photocurrents generated by bacteriorhodopsin on planar bilayer membranes

Contact Info

Product

Resources

About

LINEAR DICHROISM(250–700 nm) OF CHLOROPHYLL a AND PHEOPHYTIN a ORIENTED IN A LAMELLAR PHASE OF GLYCERYLMONOOCTANOATE/H₂O. CHARACTERIZATION OF ELECTRONIC TRANSITIONS