Backbone dynamics of an atypical orphan response regulator protein, Helicobacter pylori 1043

Ki Woong Jeong, Hyunsook Ko, Sung Ah Lee, Eunmi Hong, Sunggeon Ko, Hyun Soo Cho, Weontae Lee, Yangmee Kim

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Abstract

An atypical orphan response regulator protein, HP1043 (HP-RR) in Helicobacter pylori, is proven to be essential for cell growth and does not require the well known phosphorelay scheme. HP-RR was identified as a symmetric dimer with two functional domains, an N-terminal regulatory domain (HP-RR r) and a C-terminal effector domain (HP-RRe). HP-RR is a new class of response regulator, as a phosphorylation-independent regulator. Previously, we have presented a detailed three-dimensional structure of HP-RR using NMR spectroscopy and X-ray crystallography. In this study, in order to understand the functional importance of flexibilities in HP-RRr and HP-RRe, T1, T2, heteronuclear NOE experiments have been performed and backbone dynamics of HP-RRr and HP-RR e were investigated. HP-RRr is a symmetric dimer and the interface region, α4-β5-α5 of dimer, showed high rigidity (high S 2 values). Site of rearrangements associated with phosphorylation of HP-RRr (Ser75: R ex = 3.382, Ile 95: R ex = 5.228) showed slow chemical exchanges. HP-RRe is composed of three α-helices flanked on two sides by anti-parallel β-sheets. Low order parameters as well as conformational exchanges in the centers of loop regions known as the DNA binding site and transcription site of HP-RRe suggested that flexibility of HP-RR e is essential for interaction with DNA. In conclusion, backbone dynamics information for HP-RR implies that structural flexibilities in HP-RRr are necessary for the phosphorylation site and the dynamic nature of HP-RRe is essential for the regulation of interaction between protein and DNA.

Original languageEnglish
Pages (from-to)158-165
Number of pages8
JournalMolecules and cells
Volume35
Issue number2
DOIs
Publication statusPublished - 2013 Feb 1

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All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology

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