title: Backbone dynamics of an atypical orphan response regulator protein, Helicobacter pylori 1043.
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-RR(e)). 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-RR(r) and HP-RR(e), T1, T2, heteronuclear NOE experiments have been performed and backbone dynamics of HP-RR(r) and HP-RR(e) were investigated. HP-RR(r) 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-RR(r) (Ser(75): R ex = 3.382, Ile(95): R ex = 5.228) showed slow chemical exchanges. HP-RR(e) 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-RR(e) 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-RR(r) are necessary for the phosphorylation site and the dynamic nature of HP-RR(e) is essential for the regulation of interaction between protein and DNA.
authors: Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Institute of SMART Biotechnology, Konkuk University, Seoul 143-701, Korea.
authors: Ki-Woong
authors: KW
authors: Jeong
authors: Hyunsook
authors: H
authors: Ko
authors: Sung-Ah
authors: SA
authors: Lee
authors: Eunmi
authors: E
authors: Hong
authors: Sunggeon
authors: S
authors: Ko
authors: Hyun-Soo
authors: HS
authors: Cho
authors: Weontae
authors: W
authors: Lee
authors: Yangmee
authors: Y
authors: Kim
mesh_terms: D001665:Binding Sites; D004269:DNA, Bacterial / Q000378:metabolism*; D016480:Helicobacter pylori / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D010766:Phosphorylation; D011487:Protein Conformation; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; C501059:HP1043 protein, Helicobacter pylori; D014157:Transcription Factors