Analysis of photosynthetic pigments

Historically the first X-ray structure [43-45] to undergo exciton analysis was that of the water-soluble BChl a-protein from the green photosynthetic bacterium Prosthecochloris aestuarii. The analysis [16] raised questions, and controversies, that remain unresolved after a decade. It is reviewed again here to emphasize these difficulties, to correct some misconceptions in the literature [4,46,47] regarding possible sources of the difficulties, and to discuss more recent developments. Exciton analysis of photosynthetic pigment-protein complexes is iipt likely to become a truly useful procedure until it produces results that agree with all relevant spectra of this particular complex. 

Bertrand, M., Garrido, J., and Schoefs, B. 2004. Analysis of photosynthetic pigments An update. 

Darko, E., Schoefs, B., and Schoefs, B. 2000. An improved LC method for the analysis of photosynthetic pigments of higher plants. J. Chromatogr. 876A, 111-116. 

Iriyama, K., Yoshiura, M., and Shiraki, M., Micro-method for the qualitative and quantitative analysis of photosynthetic pigments using high-performance liquid chromatography, J. Chromatogr., 154, 302, 1978. 

Leaves of gabaculine-treated plants appear pale yellow, and pigment analysis shows a specific effect only on chlorophyll and phytochrome. " Detailed analysis of photosynthetic pigments in gabaculine-treated plants shows a greater effect on chlorophyll biosynthesis in leaves which develop after treatment (Table 5.1). Leaf expansion continues in the absence of chlorophyll biosynthesis, and after seven days, once expansion is complete. 

HPLC ANALYSIS OF THE PIGMENTS OF PURPLE PHOTOSYNTHETIC BACTERIA... 

HPLC Analysis of the Pigments of Purple Photosynthetic Bacteria 53... 

Quantitation may be carried out either by densitometry, often using HPTLC, or by recovering the separated zones from the plates and measuring them by spectrophotometry in solution. The latter method has been successfully employed for the analysis of various pigments, e.g. flavonoids (4), anthocyanins (5), photosynthetic pigments (6), porphyrins (7,8). All densitometric measurements given in this chapter were performed with a Desaga Quick Scan R D (Helena Laboratories) apparatus. 

The analysis of carotenoid identity, conformation, and binding in vivo should allow further progress to be made in understanding of the functions of these pigments in the photosynthetic machinery. One of the obvious steps toward improvement could be the use of continuously tuneable laser systems in order to obtain more detailed resonance Raman excitation profiles (Sashima et al 2000). This technique will be suitable for the investigation of in vivo systems with more complex carotenoid composition. In addition, this method may be applied for the determination of the energy of forbidden Sj or 2 Ag transition. This is an important parameter, since it allows an assessment of the energy transfer relationship between the carotenoids and chlorophylls within the antenna complex. 

Absorption and Raman analysis of LHCII complexes from xanthophyll biosynthesis mutants and plants containing unusual carotenoids (e.g., lactucoxanthin and lutein-epoxide) should also be interesting, since the role of these pigments and their binding properties are unknown. Understanding the specificity of binding can help to understand the reasons for xanthophyll variety in photosynthetic antennae and aid in the discovery of yet unknown functions for these molecules. 

Photoelastic modulation in CD analysis of. see also Circular dichroism proteins, 219, 221-222 Photosynthetic pigment, see Carotenoids Chlorophylls... 

This protocol focuses on the analysis of chlorophyll a and b, and the more nonpolar derivatives, including pheophytins and pyropheophytins. An octadecyl-bonded, reversed-phase stationary phase is used with a methanol/water mixture and ethyl acetate mobile phases in a gradient elution to provide rapid and complete separation of the major chlorophyll derivatives in 25 to 30 min. This is coupled with traditional UV/visible spectrophotometric detection at 654 nm to selectively screen these photosynthetic pigments in food and plant tissues. 

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