1l1o
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(New page: 200px<br /> <applet load="1l1o" size="450" color="white" frame="true" align="right" spinBox="true" caption="1l1o, resolution 2.80Å" /> '''Structure of the hu...)
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Revision as of 15:49, 12 November 2007
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Structure of the human Replication Protein A (RPA) trimerization core
Overview
The human single-stranded DNA-binding protein, replication protein A (RPA), binds DNA in at least two different modes: initial [8-10 nucleotides (nt)], and stable ( approximately 30 nt). Switching from 8 to 30 nt mode is, associated with a large conformational change. Here we report the 2.8 A, structure of the RPA trimerization core comprising the C-terminal, DNA-binding domain of subunit RPA70 (DBD-C), the central DNA-binding, domain of subunit RPA32 (DBD-D) and the entire RPA14 subunit. All three, domains are built around a central oligonucleotide/oligosaccharide binding, (OB)-fold and flanked by a helix at the C-terminus. Trimerization is, mediated by three C-terminal helices arranged in parallel. The OB-fold of, DBD-C possesses unique structural features; embedded zinc ribbon and, helix-turn-helix motifs. Using time-resolved proteolysis with trypsin, we, demonstrate that the trimerization core does not contribute to the binding, with substrates of 10 nt, but interacts with oligonucleotides of 24 nt., Taken together, our data indicate that switching from 8-10 to 30 nt mode, is mediated by DNA binding with the trimerization core.
About this Structure
1L1O is a Protein complex structure of sequences from Homo sapiens with ZN as ligand. Full crystallographic information is available from OCA.
Reference
Structure of the RPA trimerization core and its role in the multistep DNA-binding mechanism of RPA., Bochkareva E, Korolev S, Lees-Miller SP, Bochkarev A, EMBO J. 2002 Apr 2;21(7):1855-63. PMID:11927569
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