کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1938429 1050739 2007 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Site-directed mutagenesis of conserved aromatic residues in rat squalene epoxidase
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Site-directed mutagenesis of conserved aromatic residues in rat squalene epoxidase
چکیده انگلیسی

Squalene epoxidase catalyzes the conversion of squalene to (3S)2,3-oxidosqualene, which is a rate-limiting step of the cholesterol biogenesis. To evaluate the importance of conserved aromatic residues, 15 alanine-substituted mutants were constructed and tested for the enzyme activity. Except F203A, all the mutants significantly lost the enzyme activity, confirming the importance of the residues, either for correct folding of the protein, or for the catalytic machinery of the enzyme. Further, interestingly, F223A mutant no longer accepted (3S)2,3-oxidosqualene as a substrate, while Y473A mutant converted (3S)2,3-oxidosqualene to (3S,22S)2,3:22,23-dioxidosqualene twice more efficiently than wild-type enzyme. It is remarkable that the single amino acid replacement yielded mutants with altered substrate and product specificities. These aromatic residues are likely to be located at the substrate-binding domain of the active-site, and control the stereochemical course of the enzyme reaction.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochemical and Biophysical Research Communications - Volume 352, Issue 1, 5 January 2007, Pages 259–263
نویسندگان
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