کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1318200 1499483 2006 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
An engineered bifunctional high affinity iron uptake protein in the yeast plasma membrane
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی معدنی
پیش نمایش صفحه اول مقاله
An engineered bifunctional high affinity iron uptake protein in the yeast plasma membrane
چکیده انگلیسی
High affinity iron uptake in fungi is supported by a plasma membrane protein complex that includes a multicopper ferroxidase enzyme and a ferric iron permease. In Saccharomyces cerevisiae, this complex is composed of the ferroxidase Fet3p and the permease Ftr1p. FeII serves as substrate for Fe-uptake by being substrate for Fet3p; the resulting Fet3p-produced FeIII is then transported across the membrane via Ftr1p. A model of metabolite channeling of this FeIII is tested here by first constructing and kinetically characterizing in Fe-uptake two Fet3p-Ftr1p chimeras in which the multicopper oxidase/ferroxidase domain of Fet3p has been fused to the Ftr1p iron permease. Although the bifunctional chimeras are as kinetically efficient in Fe-uptake as is the wild type two-component system, they lack the adaptability and fidelity in Fe-uptake of the wild type. Specifically, Fe-uptake through the Fet3p, Ftr1p complex is insensitive to a potential FeIII trapping agent - citrate - whereas Fe-uptake via the chimeric proteins is competitively inhibited by this FeIII chelator. This inhibition does not appear to be due to scavenging Fet3p-produced FeIII that is in equilibrium with bulk solvent but could be due to leakiness to citrate found in the bifunctional but not the two-component system. The data are consistent with a channeling model of Fe-trafficking in the Fet3p, Ftr1p complex and suggest that in this system, Fet3p serves as a redox sieve that presents FeIII specifically for permeation through Ftr1p.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Inorganic Biochemistry - Volume 100, Issues 5–6, May 2006, Pages 1053-1060
نویسندگان
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