1y6u
From Proteopedia
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'''The Structure of the Excisionase (Xis) Protein from Conjugative Transposon Tn916 Provides Insights into the Regulation of Heterobivalent Tyrosine Recombinases''' | '''The Structure of the Excisionase (Xis) Protein from Conjugative Transposon Tn916 Provides Insights into the Regulation of Heterobivalent Tyrosine Recombinases''' | ||
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[[Category: Clubb, R T.]] | [[Category: Clubb, R T.]] | ||
[[Category: Iwahara, M.]] | [[Category: Iwahara, M.]] | ||
| - | [[Category: | + | [[Category: Conjugative transposon]] |
| - | [[Category: | + | [[Category: Dna architectural protein]] |
| - | [[Category: | + | [[Category: Excisionase]] |
| - | [[Category: | + | [[Category: Nmr structure]] |
| - | [[Category: | + | [[Category: Tyrosine recombinase]] |
| - | [[Category: | + | [[Category: Winged-helix protein]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 15:56:32 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 12:56, 3 May 2008
The Structure of the Excisionase (Xis) Protein from Conjugative Transposon Tn916 Provides Insights into the Regulation of Heterobivalent Tyrosine Recombinases
Overview
Heterobivalent tyrosine recombinases play a prominent role in numerous bacteriophage and transposon recombination systems. Their enzymatic activities are frequently regulated at a structural level by excisionase factors, which alter the ability of the recombinase to assemble into higher-order recombinogenic nucleoprotein structures. The Tn916 conjugative transposon spreads antibiotic resistance in pathogenic bacteria and is mobilized by a heterobivalent recombinase (Tn916Int), whose activity is regulated by an excisionase factor (Tn916Xis). Unlike the well-characterized (lambda)Xis excisionase from bacteriophage lambda, Tn916Xis stimulates excision in vitro and in Escherichia coli only modestly. To gain insights into this functional difference, we have performed in vitro DNA-binding studies of Tn916Xis and Tn916Int, and we have solved the solution structure of Tn916Xis. We show that the heterobivalent Tn916Int protein is capable of bridging the DR2-type and core-type sites on the left arm of the tranpsoson. Consistent with the notion that Tn916Int is regulated only loosely, we find that Tn916Xis binding does not alter the stability of DR2-Tn916Int-core bridges or the ability of Tn916Int to recognize the arms of the transposon in vitro. Despite a high degree of divergence at the primary sequence level, we show that Tn916Xis and (lambda)Xis adopt related prokaryotic winged-helix structures. However, they differ at their C termini, with Tn916Xis replacing the flexible integrase contacting tail found in (lambda)Xis with a positively charged alpha-helix. This difference provides a structural explanation for why Tn916Xis does not interact cooperatively with its cognate integrase in vitro, and reveals how subtle changes in the winged-helix fold can modulate the functional properties of excisionase factors.
About this Structure
1Y6U is a Single protein structure of sequence from Enterococcus faecalis. Full crystallographic information is available from OCA.
Reference
The structure of the excisionase (Xis) protein from conjugative transposon Tn916 provides insights into the regulation of heterobivalent tyrosine recombinases., Abbani M, Iwahara M, Clubb RT, J Mol Biol. 2005 Mar 18;347(1):11-25. Epub 2005 Jan 19. PMID:15733914 Page seeded by OCA on Sat May 3 15:56:32 2008
