کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5376413 | 1389359 | 2007 | 13 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Photo dynamics of BLUF domain mutant H44R of AppA from Rhodobacter sphaeroides
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کلمات کلیدی
FMNRhodobacter sphaeroidesFlavinsAPPACharge recombination - بازسازی شارژFAD - بدPhoto-degradation - تخریب عکسRiboflavin - ریبوفلاوین، ویتامین B2Absorption spectroscopy - طیف سنجی جذبPhoto-cycle - عکس چرخهBlue-light photoreceptor - فتوتراپی آبی نورFlavoprotein - فلاوپروتئینFluorescence spectroscopy - فوتولومینسانس یا فلوئورسانس یا فسفرسانس
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Photo dynamics of BLUF domain mutant H44R of AppA from Rhodobacter sphaeroides Photo dynamics of BLUF domain mutant H44R of AppA from Rhodobacter sphaeroides](/preview/png/5376413.png)
چکیده انگلیسی
The photo-cycle dynamics of the H44R mutant of the BLUF domain of the transcriptional anti-repressor protein AppA (AppA-H44R) from the non-sulfur anoxyphototropic purple bacterium Rhodobacter sphaeroides is studied in order to gain information on the involvement of His44 in the photo-cyclic mechanism of the AppA BLUF domain and to add information to the involved processes. The amino acid residue histidine at position 44 is replaced by arginine. A 12 nm red-shifted signalling state is formed upon blue-light excitation, while in wild-type AppA (AppA-wt) the red-shift is 16 nm. The recovery to the receptor dark state is approximately a factor of 2.5 faster (Ïrec â 6.5 min) than the recovery of the wild-type counterpart. Extended light exposure of the mutant causes photo-degradation of flavin (mainly free flavin conversion to lumichrome and re-equilibration between free and non-covalently bound flavin) and protein aggregation (showing up as light scattering). No photo-degradation was observed for AppA-wt. The quantum efficiency of signalling-state formation determined by intensity dependent absorption measurements is found to be Ïs â 0.3 (for AppA-wt: Ïs â 0.24). A two-component single-exponential fluorescence relaxation was observed, which is interpreted as fast fluorescence quenching to an equilibrium value by photo-induced electron transfer followed by slower fluorescence decay due to charge recombination. Based on the experimental findings, an extended photo-cycle model for BLUF domains is proposed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Physics - Volume 335, Issue 1, 21 May 2007, Pages 15-27
Journal: Chemical Physics - Volume 335, Issue 1, 21 May 2007, Pages 15-27
نویسندگان
P. Zirak, A. Penzkofer, P. Hegemann, T. Mathes,