کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2186799 1096079 2009 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Structural Stabilities of Different Regions of the Titin I27 Domain Contribute Differently to Unfolding upon Mitochondrial Protein Import
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی بیولوژی سلول
پیش نمایش صفحه اول مقاله
Structural Stabilities of Different Regions of the Titin I27 Domain Contribute Differently to Unfolding upon Mitochondrial Protein Import
چکیده انگلیسی

Protein import into mitochondria requires unfolding of the folded mature domain of precursor proteins. Here we compared the effects of amino-acid replacement between the core region and the N-terminal region of the titin I27 domain (the 27th Ig domain of human titin) on its import into isolated mitochondria when attached to a short presequence (pb2(35)). We found that several mutations in the core region around Trp34 of the I27 domain enhanced the import rates of the fusion proteins, while the N-terminal K6P mutation, which increases mechanical stability around the N-terminal region, decreases the import rate. When the K6P mutation is combined with core-destabilizing mutations, the import rates of the fusion proteins still decrease, unless a long segment is deleted. These results suggest that mutations in the core region could destabilize the transition state for unfolding from the intermediate with the detached N-terminal segment during import, leading to enhanced unfolding rates, although stabilization of the N-terminal region masks these effects. In other words, the rate-limiting step of the global unfolding upon import into mitochondria switches, depending on the balance between the stability of the N-terminal structure and the stability of the core region of the I27 domain.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Biology - Volume 385, Issue 3, 23 January 2009, Pages 811–819
نویسندگان
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