کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2188322 1096162 2007 21 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The Structurally Disordered KRAB Repression Domain Is Incorporated into a Protease Resistant Core upon Binding to KAP-1-RBCC Domain
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی بیولوژی سلول
پیش نمایش صفحه اول مقاله
The Structurally Disordered KRAB Repression Domain Is Incorporated into a Protease Resistant Core upon Binding to KAP-1-RBCC Domain
چکیده انگلیسی

The KRAB domain is a 75 amino acid transcriptional repression module that is encoded by more than 400 zinc finger protein genes, making it the most abundant repression domain in the human proteome. KRAB-mediated gene silencing requires a direct high affinity interaction with the RBCC domain of KAP-1 co-repressor. The structures of the free KRAB domain or the KRAB–RBCC complex are unknown. To address this, we have performed a systematic biophysical analysis of all KRAB isoforms using purified recombinant proteins. All KRAB domains are predominantly monomeric either alone or in a complex with KAP-1–RBCC protein, while a KRAB–SCAN isoform exists as a stable dimer. The KRAB:KAP-1–RBCC interaction requires only the A box in the context of the KRAB(Ab) or KRAB(AC) but both A and B boxes in the context of KRAB(AB). All isoforms bind the KAP-1–RBCC in a stable, zinc dependent fashion with a stoichiometry of KRAB1:3 RBCC with a zinc content of four atoms per RBCC monomer. Limited proteolysis, mass spectrometry and N-terminal sequence analyses suggest that a core complex comprises the entire RBCC domain of KAP-1 and the AB box of the KRAB domain rendering it resistant to proteolysis. NMR spectroscopy showed that unbound KRAB domain does not exist as a well-folded globular protein in solution but may fold into an ordered structure upon binding to the KAP-1–RBCC protein. This is the first example of a structurally disordered repressor domain that is the most widely conserved silencing domain in tetrapods.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Biology - Volume 370, Issue 2, 6 July 2007, Pages 269–289
نویسندگان
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