3c57
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Revision as of 06:52, 24 April 2008
Crystal Structure of the Mycobacterium tuberculosis Hypoxic Response Regulator DosR C-terminal Domain Crystal Form II
Overview
The response regulator DosR is essential for promoting long-term survival of Mycobacterium tuberculosis under low oxygen conditions in a dormant state and may be responsible for latent tuberculosis in one-third of the world's population. Here, we report crystal structures of full-length unphosphorylated DosR at 2.2 A resolution and its C-terminal DNA-binding domain at 1.7 A resolution. The full-length DosR structure reveals several features never seen before in other response regulators. The N-terminal domain of the full-length DosR structure has an unexpected (beta alpha)(4) topology instead of the canonical (beta alpha)(5) fold observed in other response regulators. The linker region adopts a unique conformation that contains two helices forming a four-helix bundle with two helices from another subunit, resulting in dimer formation. The C-terminal domain in the full-length DosR structure displays a novel location of helix alpha 10, which allows Gln199 to interact with the catalytic Asp54 residue of the N-terminal domain. In contrast, the structure of the DosR C-terminal domain alone displays a remarkable unstructured conformation for helix alpha 10 residues, different from the well-defined helical conformations in all other known structures, indicating considerable flexibility within the C-terminal domain. Our structures suggest a mode of DosR activation by phosphorylation via a helix rearrangement mechanism.
About this Structure
3C57 is a Single protein structure of sequence from Mycobacterium tuberculosis. Full crystallographic information is available from OCA.
Reference
Crystal structures of the response regulator DosR from Mycobacterium tuberculosis suggest a helix rearrangement mechanism for phosphorylation activation., Wisedchaisri G, Wu M, Sherman DR, Hol WG, J Mol Biol. 2008 Apr 18;378(1):227-42. Epub 2008 Feb 26. PMID:18353359 Page seeded by OCA on Thu Apr 24 09:52:08 2008
