Spectral Properties of Isolated Photosystem II Reaction Center Complex at 77K

Tetenkin, V. L.; Gulyaev, B. A.; Rubin, A. B.; Seibert, M.

doi:10.1007/978-94-009-0511-5_95

Cited by 1 publication

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“…It does not undergo the complex multi-photon redox transformations of a functional PS II core. Although isolated RC preparations have been shown to be variable and heterogeneous [5] , the absence of the many metastable photo-chemical steps which plague any study of PS II core complexes means that they have been utilised in many studies. A very wide range of spectroscopies have been performed on isolated RCs.…”

Section: Introductionmentioning

confidence: 99%

New Perspectives on Photosystem II Reaction Centres

et al. 2020

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We apply the differential optical spectroscopy techniques of circular polarisation of luminescence (CPL) and magnetic CPL (MCPL) to the study of isolated reaction centres (RCs) of photosystem II (PS II). The data and subsequent analysis provide insights into aspects of the RC chromophore site energies, exciton couplings, and heterogeneities. CPL measurements are able to identify weak luminescence associated with the unbound chlorophyll-a (Chl-a) present in the sample. The overall sign and magnitude of the CPL observed relates well to the circular dichroism (CD) of the sample. Both CD and CPL are reasonably consistent with modelling of the RC exciton structure. The MCPL observed for the free Chl-a luminescence component in the RC samples is also easily understandable, but the MCPL seen near 680nm at 1.8K is anomalous, appearing to have a narrow, strongly negative component. A negative sign is inconsistent with MCPL of (exciton coupled) Qy states of either Chl-a or pheophytin-a (Pheo-a). We propose that this anomaly may arise as a result of the luminescence from a transient excited state species created following photo-induced charge separation within the RC. A comparison of CD spectra and modelling of RC preparations having a different number of pigments suggests that the non-conservative nature of the CD spectra observed is associated with the ‘special pair’ pigments PD1 and PD2.

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Section: Introductionmentioning

confidence: 99%