Acceleration of the excitation decay in Photosystem I immobilized on glass surface

• Published in: Photosynthesis research Vol. 136; no. 2; pp. 171 - 181
• Main Authors: Szewczyk, Sebastian, Giera, Wojciech, Białek, Rafał, Burdziński, Gotard, Gibasiewicz, Krzysztof
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-05-2018; Springer; Springer Nature B.V
• Subjects: Biochemistry; Biomedical and Life Sciences; Chlorophyll - metabolism; Dehydration; Energy Transfer; Fluorine - chemistry; Glass; Glass substrates; Immobilized Proteins - chemistry; Immobilized Proteins - metabolism; Kinetics; Life Sciences; Original; Original Article; Photosynthesis; Photosystem I; Photosystem I Protein Complex - chemistry; Photosystem I Protein Complex - metabolism; Plant Genetics and Genomics; Plant Physiology; Plant Sciences; Proteins; Synechocystis - metabolism; Tin Compounds - chemistry; X-Ray Absorption Spectroscopy; Cyanobacteria; Photosystem I; Excitation energy transfer; Biophotovoltaics; Red chlorophylls; Transient absorption spectroscopy; Conductive glass
• ISSN: 0166-8595; 1573-5079
• DOI: 10.1007/s11120-017-0454-z

Femtosecond transient absorption was used to study excitation decay in monomeric and trimeric cyanobacterial Photosystem I (PSI) being prepared in three states: (1) in aqueous solution, (2) deposited and dried on glass surface (either conducting or non-conducting), and (3) deposited on glass (conducting) surface but being in contact with aqueous solvent. The main goal of this contribution was to determine the reason of the acceleration of the excitation decay in dried PSI deposited on the conducting surface relative to PSI in solution observed previously using time-resolved fluorescence (Szewczyk et al., Photysnth Res 132(2):111–126, 2017). We formulated two alternative working hypotheses: (1) the acceleration results from electron injection from PSI to the conducting surface; (2) the acceleration is caused by dehydration and/or crowding of PSI proteins deposited on the glass substrate. Excitation dynamics of PSI in all three types of samples can be described by three main components of subpicosecond, 3–5, and 20–26 ps lifetimes of different relative contributions in solution than in PSI-substrate systems. The presence of similar kinetic components for all the samples indicates intactness of PSI proteins after their deposition onto the substrates. The kinetic traces for all systems with PSI deposited on substrates are almost identical and they decay significantly faster than the kinetic traces of PSI in solution. We conclude that the accelerated excitation decay in PSI-substrate systems is caused mostly by dense packing of proteins.