Investigation of the molecular mechanism of the blue-light-specific excitation energy quenching in the plant antenna complex LHCII

Spectroscopy of Photosynthetic Pigment-Protein Complex LHCII

“…3, light-induced excitation quenching induced by blue light, absorbed both by chlorophylls and carotenoids, is much more effective that in the case of red light, absorbed exclusively by chlorophylls, despite equalized energy absorbed by LHCII in these two spectral regions. Moreover, the chlorophyll fluorescence lifetime analysis in LHCII shows that the lifetime distributions recorded with blue light are shifted towards lower values as compared to the distributions recorded with red light [14,15]. Such an observation suggests involvement of the LHCII-built xanthophylls in light-driven excitation quenching.…”

“…The presence of these components can be interpreted as representing the intermolecular interactions of LHCII, leading to formation of molecular aggregates. Interestingly, illumination of LHCII with blue light, which results in light-induced molecular configuration changes of violaxanthin and neoxanthin and light-driven singlet excitation quenching, results also in a reversible, light-induced reorganization of the complex, manifested by changes in the structure of the amide I spectral band [15]. The main effect of illumination on the infrared absorption spectra of LHCII can be attributed to formation of intermolecular hydrogen bonds at expense of the turns and loops structures [15].…”

Light-Induced Infrared Difference Spectroscopy in the Investigation of Light Harvesting Complexes

“…This approach is useful only in case of long-lived processes (τ > ~5 s) because, without the use of specific software, the recording of the first spectrum after the background starts some hundredth of milliseconds (or even more) after the end of the illumination; furthermore, this recording requires at least some seconds. Several applications of this approach have been reported for isolated LHCs, LHC-containing systems or related proteins [13,18,19,27,28]. A modified version of this approach (the difference is made using two spectra from different samples, a procedure which may be applied when relatively big spectral changes are expected) has also been reported [20,21].…”

“…The list of studied systems include: RC-LHI supercomplexes from purple bacteria [9], chromatophores from purple bacteria ([8,10,11,12,13,14,15] and refs. therein), LHCII from plants [5,16,17,18,19,20], CP43 and CP47 from plants [5], thylakoids [8,21], Peridinin-Chlorophyll a -proteins from Amphidinium carterae (A-PCP) [22,23,24,25] and Heterocapsa Pygmaea (H-PCP) [26]; to this list, a non-light-harvesting protein playing a crucial role in photoprotection of cyanobacteria, Orange Carotenoid Protein (OCP), should be added [27,28].…”

Structure–Function Relationship of the Plant Photosynthetic Pigment–Protein Complex LHCII Studied with Molecular Spectroscopy Techniques

“…Singlet electronic excitations at chlorophyll molecules, which are not transferred out of the complex, are a potential source of triplet states, singlet oxygen, and oxidation-induced damage. The process depends also on light quality, despite the fact that the number of light quanta absorbed by the sample was equalized (Gruszecki et al, 2010(Gruszecki et al, , 2011. On the other hand, in terms of photoprotection at the level of a single LHCII complex the risk of light-induced damage would be essentially diminished by quenching of excessive singlet excitations, before chlorophyll triplets are formed.…”