کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1943619 1537054 2006 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Tight binding of NADPH to the 39-kDa subunit of complex I is not required for catalytic activity but stabilizes the multiprotein complex
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک دانش گیاه شناسی
پیش نمایش صفحه اول مقاله
Tight binding of NADPH to the 39-kDa subunit of complex I is not required for catalytic activity but stabilizes the multiprotein complex
چکیده انگلیسی

In addition to the 14 central subunits, respiratory chain complex I from the aerobic yeast Yarrowia lipolytica contains at least 24 accessory subunits, most of which are poorly characterized. Here we investigated the role of the accessory 39-kDa subunit which belongs to the heterogeneous short-chain dehydrogenase/reductase (SDR) enzyme family and contains non-covalently bound NADPH. Deleting the chromosomal copy of the gene that codes for the 39-kDa subunit drastically impaired complex I assembly in Y. lipolytica. We introduced several site-directed mutations into the nucleotide binding motif that severely reduced NADPH binding. This effect was most pronounced when the arginine at the end of the second β-strand of the NADPH binding Rossman fold was replaced by leucine or aspartate. Mutations affecting nucleotide binding had only minor or moderate effects on specific catalytic activity in mitochondrial membranes but clearly destabilized complex I. One mutant exhibited a temperature sensitive phenotype and significant amounts of three different subcomplexes were observed even at more permissive temperature. We concluded that the 39-kDa subunit of Y. lipolytica plays a critical role in complex I assembly and stability and that the bound NADPH serves to stabilize the subunit and complex I as a whole rather than serving a catalytic function.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1757, Issue 12, December 2006, Pages 1676–1682
نویسندگان
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