کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6493828 | 44426 | 2015 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Characterization of the structural changes and photochemical activity of photosystem I under Al3+ effect
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کلمات کلیدی
DQH2cytochrome b6/f complexTMPDPSILight harvesting complex IPSIIChlLHCINaN3P700Cyt b6/fDCMU3-(3,4-Dichlorophenyl)-1,1-dimethylurea - 3- (3،4-Dichlorophenyl) -1،1-dimethylureaAluminum - آلومینیوم Fourier transform infra red - تبدیل فوریه مادون قرمزProtein secondary structure - ساختار ثانویه پروتئینChlorophyll - سبزینه یا کلروفیلsodium azide - سدیم آیزیدFTIR - طیف سنج مادون قرمزphotosystem I - عکس سیستم منPhotosystem II - فتوسیستم 2Methyl viologen - متیل ویولونگreaction center - مرکز واکنشFar red light - نور قرمز دورPlastocyanin - پلاستوسیانین
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
بیو مهندسی (مهندسی زیستی)
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The photochemical activity of photosystem I (PSI) as affected by Al3+ was investigated in thylakoid membranes and PSI submembrane fractions isolated from spinach. Biophysical and biochemical techniques such as oxygen uptake, light induced absorbance changes at 820 nm, chlorophyll fluorescence emission, SDS-polyacrylamide gel electrophoresis, and FTIR spectroscopy have been used to analyze the sites and action modes of this cation on the PSI complex. Our results showed that Al3+ above 3 mM induces changes in the redox state of P700 reflected by an increase of P700 photooxidation phase and a delay of the slower rate of P700 re-reduction which reveals that Al3+ exerted an inhibitory action at the donor side of PSI especially at plastocyanin (PC). Furthermore, results of P700 photooxidation monitored in the presence of DCMU with or without MV suggested that the same range of Al3+ concentrations impairs the photochemical reaction centers (RC) of PSI, as shown by the decline in the amount of active population of P700, and disrupts the charge separation between P700 and the primary electron acceptor A0 leading to the inhibition of electron transfer at the acceptor side of PSI. These inhibitory actions were also accompanied by an impairment of the energy transfer from light harvesting complex (LHCI) to RC of PSI, following the disconnection of LHCI antenna as illustrated by an enhancement of chlorophyll fluorescence emission spectra at low temperature (77 K). The above results coincided with FTIR measurements that indicated a conformational change of the protein secondary structures in PSI complex where 25% of α-helix was converted into β-sheet, β-antiparallel and turn structures. These structural changes in PSI complex proteins are closely related with the alteration photochemical activity of PSI including the inhibition of the electron transport through both acceptor and donor sides of PSI.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 149, August 2015, Pages 292-299
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 149, August 2015, Pages 292-299
نویسندگان
Imed Hasni, Najoua Msilini, Saber Hamdani, Heidar-Ali Tajmir-Riahi, Robert Carpentier,