1dfa
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(New page: 200px<br /><applet load="1dfa" size="450" color="white" frame="true" align="right" spinBox="true" caption="1dfa, resolution 2.0Å" /> '''CRYSTAL STRUCTURE OF ...)
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Revision as of 11:07, 20 November 2007
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CRYSTAL STRUCTURE OF PI-SCEI IN C2 SPACE GROUP
Overview
The PI-SceI protein is an intein-encoded homing endonuclease that, initiates the mobility of its gene by making a double strand break at a, single site in the yeast genome. The PI-SceI protein splicing and, endonucleolytic active sites are separately located in each of two domains, in the PI-SceI structure. To determine the spatial relationship between, bases in the PI-SceI recognition sequence and selected PI-SceI amino, acids, the PI-SceI-DNA complex was probed by photocross-linking and, affinity cleavage methods. Unique solvent-accessible cysteine residues, were introduced into the two PI-SceI domains at positions 91, 97, 170, 230, 376, and 378, and the mutant proteins were modified with either, 4-azidophenacyl bromide or iron, (S)-1-(p-bromoacetamidobenzyl)-ethylenediaminetetraacetate (FeBABE). The, phenyl azide-coupled proteins cross-linked to the PI-SceI target sequence, and the FeBABE-modified proteins cleaved the DNA proximal to the, derivatized amino acid. The results suggest that an extended beta-hairpin, loop in the endonuclease domain that contains residues 376 and 378, contacts the major groove near the PI-SceI cleavage site. Conversely, residues 91, 97, and 170 in the protein splicing domain are in close, proximity to a distant region of the substrate. To interpret our results, we used a new PI-SceI structure that is ordered in regions of the protein, that bind DNA. The data strongly support a model of the PI-SceI-DNA, complex derived from this structure.
About this Structure
1DFA is a Single protein structure of sequence from Saccharomyces cerevisiae. Active as H(+)-transporting two-sector ATPase, with EC number 3.6.3.14 Full crystallographic information is available from OCA.
Reference
Probing the structure of the PI-SceI-DNA complex by affinity cleavage and affinity photocross-linking., Hu D, Crist M, Duan X, Quiocho FA, Gimble FS, J Biol Chem. 2000 Jan 28;275(4):2705-12. PMID:10644733
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