(iii) In chirally organized systems, e.g., in the so-called psi-type aggregates, such as DNA aggregates, condensed chromatins, and viruses, very intense CD signals have been observed, with non-conservative, anomalously shaped bands, which are accompanied by long tails outside the absorbance originating from differential scattering

of the sample (Keller and Bustamante 1986; Tinoco et al. 1987). Hierarchically organized systems, such as granal thylakoid membranes, or lamellar aggregates of LHCII (Simidjev et al. 1997), contain all the three different types of signals; they are superimposed on each other (Fig. 3). Fig. 3 Circular-dichroism PI3K inhibitor spectra exhibited by the thylakoid pigments at different levels of organization. The pigment concentrations (Selleckchem CHIR99021 adjusted to 20 μg Chl(a + b)/ml) are identical in the three samples: the acetonic (80%) extract—yielding intrinsic CD (for easier comparison, the signal is multiplied by a factor 5), pea thylakoid membranes suspended in low salt hypotonic medium (30 mM Tricine pH 7.8, 10 mM KCl, 2 mM EDTA)—dominated by the sum of the excitonic bands, and

the same membranes suspended in isotonic medium in the presence of Mg ions (the medium above is supplemented with 330 mM sorbitol and 5 mM MgCl2). (V. Barzda, M. Szabó and G. Garab, unpublished.) Intrinsic {Selleck Anti-infection Compound Library|Selleck Antiinfection Compound Library|Selleck Anti-infection Compound Library|Selleck Antiinfection Compound Library|Selleckchem Anti-infection Compound Library|Selleckchem Antiinfection Compound Library|Selleckchem Anti-infection Compound Library|Selleckchem Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|buy Anti-infection Compound Library|Anti-infection Compound Library ic50|Anti-infection Compound Library price|Anti-infection Compound Library cost|Anti-infection Compound Library solubility dmso|Anti-infection Compound Library purchase|Anti-infection Compound Library manufacturer|Anti-infection Compound Library research buy|Anti-infection Compound Library order|Anti-infection Compound Library mouse|Anti-infection Compound Library chemical structure|Anti-infection Compound Library mw|Anti-infection Compound Library molecular weight|Anti-infection Compound Library datasheet|Anti-infection Compound Library supplier|Anti-infection Compound Library in vitro|Anti-infection Compound Library cell line|Anti-infection Compound Library concentration|Anti-infection Compound Library nmr|Anti-infection Compound Library in vivo|Anti-infection Compound Library clinical trial|Anti-infection Compound Library cell assay|Anti-infection Compound Library screening|Anti-infection Compound Library high throughput|buy Antiinfection Compound Library|Antiinfection Compound Library ic50|Antiinfection Compound Library price|Antiinfection Compound Library cost|Antiinfection Compound Library solubility dmso|Antiinfection Compound Library purchase|Antiinfection Compound Library manufacturer|Antiinfection Compound Library research buy|Antiinfection Compound Library order|Antiinfection Compound Library chemical structure|Antiinfection Compound Library datasheet|Antiinfection Compound Library supplier|Antiinfection Compound Library in vitro|Antiinfection Compound Library cell line|Antiinfection Compound Library concentration|Antiinfection Compound Library clinical trial|Antiinfection Compound Library cell assay|Antiinfection Compound Library screening|Antiinfection Compound Library high throughput|Anti-infection Compound high throughput screening| CD of photosynthetic pigment molecules In monomeric solutions, chlorophylls and carotenoids exhibit very weak CD signals: for 1 absorbance unit, in the range of some 10−5 intensities. In general, molecules with planar and rather symmetric structures (such as (B)Chls) and those as rods (such as carotenoids) result in weak rotational strengths (R), which are a measure of the CD intensity (R is proportional to the scalar product of the electric and magnetic dipole moments). In most photosynthetic systems, the contributions from these intrinsic CD signals can safely be ignored or corrected, based on the absorbance band structure and the CD in the pigment solutions (cf. Fig. 3—intrinsic CD, in acetonic solution). It HA-1077 molecular weight is also possible, however, that the protein environment induces some twisting of, for instance, carotenoids or the open

ring tetrapyrrole chromophores (phycobilins) in phycobilisomes of cyanobacteria. This effect can complicate the interpretation of CD spectra, since it is hard to make quantitative estimates of its corresponding spectral shape and size. Fortunately, the conjugated ring systems of (B)Chls are not easily twisted, and for those molecules, both the intrinsic and the induced effects can be ignored. An exception has been found in a Chl a/Chl c antenna, where a strong CD band, having the same band structure as the absorbance, has been detected in a long-wavelength absorbing Chl a molecule (Büchel and Garab 1997). This CD band is most probably induced by distortion of the porphyrin ring by a charged aromatic amino acid residue (cf. Pearlstein 1991).