Nucleic Acids Research Advance Access originally published online on May 27, 2009
Nucleic Acids Research 2009 37(14):4545-4558; doi:10.1093/nar/gkp445
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Nucleic Acids Research, 2009, Vol. 37, No. 14 4545-4558
© 2009 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Structural Biology |
The structure of CrgA from Neisseria meningitidis reveals a new octameric assembly state for LysR transcriptional regulators
1The Oxford Protein Production Facility and Division of Structural Biology, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK, 2The University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK and 3The Bacterial Pathogenesis and Functional Genomics Group, The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE. UK
*To whom correspondence should be addressed. Tel: 44 (0) 1865 287748; Fax: 44 (0) 1865 287748; Email: ray{at}strubi.ox.ac.uk
Received December 5, 2008. Revised April 21, 2009. Accepted May 11, 2009.
LysR-type transcriptional regulators (LTTRs) form the largest family of bacterial regulators acting as both auto-repressors and activators of target promoters, controlling operons involved in a wide variety of cellular processes. The LTTR, CrgA, from the human pathogen Neisseria meningitidis, is upregulated during bacterial–host cell contact. Here, we report the crystal structures of both regulatory domain and full-length CrgA, the first of a novel subclass of LTTRs that form octameric rings. Non-denaturing mass spectrometry analysis and analytical ultracentrifugation established that the octameric form of CrgA is the predominant species in solution in both the presence and absence of an oligonucleotide encompassing the CrgA-binding sequence. Furthermore, analysis of the isolated CrgA–DNA complex by mass spectrometry showed stabilization of a double octamer species upon DNA binding. Based on the observed structure and the mass spectrometry findings, a model is proposed in which a hexadecameric array of two CrgA oligomers binds to its DNA target site.