2rm8

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spinqualitylabelsall models PDB ID 2rm8 Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image
Gene:	htrII (Natronomonas pharaonis)
Resources:	FirstGlance, OCA, PDBsum, RCSB
Coordinates:	save as pdb, mmCIF, xml

The solution structure of phototactic transducer protein HtrII linker region from Natronomonas pharaonis

Overview

Halobacterial pharaonis phoborhodopsin [ppR, also called Natronomonas pharaonis sensory rhodopsin II (NpSRII)] is a phototaxis protein which transmits a light signal to the cytoplasm through its transducer protein (pHtrII). pHtrII, a two-transmembrane protein that interacts with ppR, belongs to the group of methyl-accepting chemotaxis proteins (MCPs). Several mutation studies have indicated that the linker region connecting the transmembrane and methylation regions is necessary for signal transduction. However, the three-dimensional (3D) structure of an MCP linker region has yet to be reported, and hence, details concerning the signal transduction mechanism remain unknown. Here the structure of the pHtrII linker region was investigated biochemically and biophysically. Following limited proteolysis, only one trypsin resistant fragment in the pHtrII linker region was identified. This fragment forms a homodimer with a Kd value of 115 microM. The 3D structure of this fragment was determined by solution NMR, and only one alpha-helix was found between two HAMP domains of the linker region. This alpha-helix was significantly stabilized within transmembrane protein pHtrII as revealed by CW-EPR. The presence of Af1503 HAMP domain-like structures in the linker region was supported by CD, NMR, and ELDOR data. The alpha-helix determined here presumably works as a mechanical joint between two HAMP domains in the linker region to transfer the photoactivated conformational change downstream.

About this Structure

2RM8 is a Single protein structure of sequence from Natronomonas pharaonis. Full crystallographic information is available from OCA.

Reference

Structural analysis of the phototactic transducer protein HtrII linker region from Natronomonas pharaonis., Hayashi K, Sudo Y, Jee J, Mishima M, Hara H, Kamo N, Kojima C, Biochemistry. 2007 Dec 18;46(50):14380-90. Epub 2007 Nov 15. PMID:18001143

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