کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10795971 | 1052640 | 2010 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Dual role of FMN in flavodoxin function: Electron transfer cofactor and modulation of the protein-protein interaction surface
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کلمات کلیدی
DDMapoflavodoxinFAD synthetaseFNRr.m.s.d.FLDKETFADSPSIPMSKAP - CAPFerredoxin-NADP+ reductase - Feredoxin-NADP + ردوکتازelectron transfer - انتقال الکترونProtein-protein interaction - تعامل پروتئین-پروتئینElectron transfer rate constant - ثابت انتقال الکترون الکترونیکAssociation constant - ثابت انجمنDissociation constant - حد تفکیکRiboflavin - ریبوفلاوین، ویتامین B2photosystem I - عکس سیستم منFlavodoxin - فلاوودوکسینphenazine methosulfate - فنزین متوسولفاتroot mean square deviation - میانگین انحراف مربع ریشهSemiquinone - نیمه قیمتیHydroquinone - هیدروکینونReduction potential - پتانسیل کاهشkobs - کوبس
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
دانش گیاه شناسی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Flavodoxin (Fld) replaces Ferredoxin (Fd) as electron carrier from Photosystem I (PSI) to Ferredoxin-NADP+ reductase (FNR). A number of Anabaena Fld (AnFld) variants with replacements at the interaction surface with FNR and PSI indicated that neither polar nor hydrophobic residues resulted critical for the interactions, particularly with FNR. This suggests that the solvent exposed benzenoid surface of the Fld FMN cofactor might contribute to it. FMN has been replaced with analogues in which its 7- and/or 8-methyl groups have been replaced by chlorine and/or hydrogen. The oxidised Fld variants accept electrons from reduced FNR more efficiently than Fld, as expected from their less negative midpoint potential. However, processes with PSI (including reduction of Fld semiquinone by PSI, described here for the first time) are impeded at the steps that involve complex re-arrangement and electron transfer (ET). The groups introduced, particularly chlorine, have an electron withdrawal effect on the pyrazine and pyrimidine rings of FMN. These changes are reflected in the magnitude and orientation of the molecular dipole moment of the variants, both factors appearing critical for the re-arrangement of the finely tuned PSI:Fld complex. Processes with FNR are also slightly modulated. Despite the displacements observed, the negative end of the dipole moment points towards the surface that contains the FMN, still allowing formation of complexes competent for efficient ET. This agrees with several alternative binding modes in the FNR:Fld interaction. In conclusion, the FMN in Fld not only contributes to the redox process, but also to attain the competent interaction of Fld with FNR and PSI.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1797, Issue 2, February 2010, Pages 262-271
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1797, Issue 2, February 2010, Pages 262-271
نویسندگان
Susana Frago, Isaias Lans, José A. Navarro, Manuel Hervás, Dale E. Edmondson, Miguel A. De la Rosa, Carlos Gómez-Moreno, Stephen G. Mayhew, Milagros Medina,