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
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی معدنی
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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 5â6, May 2006, Pages 1053-1060
Journal: Journal of Inorganic Biochemistry - Volume 100, Issues 5â6, May 2006, Pages 1053-1060
نویسندگان
E.Y. Kwok, C.S. Stoj, S. Severance, D.J. Kosman,