Probing the conformational dynamics of photosystem I in unconfined and confined spaces. Issue 1 (6th December 2017)

• Record Type: Journal Article
• Authors: Das, Gaurav; Chattoraj, Shyamtanu; Nandi, Somen; Mondal, Prasenjit; Saha, Abhijit; Bhattacharyya, Kankan; Ghosh, Surajit
• Is Part Of: Physical chemistry chemical physics. Volume 20:Issue 1(2017)
• Page Start: 449
• Page End: 455
• Publication Date: 2017-12-06
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c7cp07375e
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : PSI demonstrates strong fluctuations in fluorescence intensity and lifetime with two conformational states in bulk-water in contrast to a liposome. Abstract : The fluorescence dynamics of Photosystem I (PSI) in bulk water and inside a confined environment like a liposome have been investigated using time resolved confocal microscopy. In bulk water, PSI exhibits a major emission peak at ∼680 nm, while in the liposome it exhibits a markedly blue shifted emission maximum at ∼485 nm. This is indicative of conformational changes due to entrapment and emergence of a stressed conformation of PSI inside the liposome. The observed time constants for the fluorescence lifetime of PSI inside the liposome are significantly high as opposed to PSI in bulk water. More interestingly, the fluorescence intensity of PSI in bulk water exhibits strong fluctuations with many high intensity jumps and these are anti-correlated with the fluorescence lifetime of PSI. In contrast, inside the liposome, no such anti-correlated behaviour is observed. We further demonstrated that PSI exhibits at least two conformational states in bulk water, whereas a single conformation is observed inside the liposome, indicating the conformational rigidity and locking of the PSI complex inside a liposome.