1D06

STRUCTURAL BASIS OF DIMERIZATION AND SENSORY MECHANISMS OF OXYGEN-SENSING DOMAIN OF RHIZOBIUM MELILOTI FIXL DETERMINED AT 1.4A RESOLUTION

1D06 の概要

• エントリーDOI: 10.2210/pdb1d06/pdb
• 分子名称: nitrogen fixation regulatory protein fixL, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• 機能のキーワード: oxygen sensor, histidine kinase, pas, high-resolution, two-component system, signaling protein
• 由来する生物種: Sinorhizobium meliloti
• 細胞内の位置: Cell inner membrane; Multi-pass membrane protein: P10955
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 15138.87

構造登録者

Miyatake, H.,Mukai, M.,Park, S.-Y.,Adachi, S.,Tamura, K.,Nakamura, H.,Nakamura, K.,Tsuchiya, T.,Iizuka, T.,Shiro, Y. (登録日: 1999-09-09, 公開日: 2000-03-15, 最終更新日: 2024-02-07)

主引用文献

Miyatake, H.,Mukai, M.,Park, S.-Y.,Adachi, S.,Tamura, K.,Nakamura, H.,Nakamura, K.,Tsuchiya, T.,Iizuka, T.,Shiro, Y.
Sensory mechanism of oxygen sensor FixL from Rhizobium meliloti: crystallographic, mutagenesis and resonance Raman spectroscopic studies
J.MOL.BIOL., 301:415-431, 2000

PubMed Abstract: FixL of Rhizobium meliloti (RmFixL) is a sensor histidine kinase of the two-component system, which regulates the expression of the genes related to nitrogen fixation in the root nodule in response to the O(2) levels. The crystal structure of the sensor domain of FixL (RmFixLH), which contains a heme (Fe-porphyrin) as a sensing site, was determined at 1.4 A resolution. Based on the structural and spectroscopic analyses, we propose the O(2) sensing mechanism that differs from the case proposed in BjFixLH as follows; conformational changes in the F/G loop, which are induced by steric repulsion between the bent-bound O(2) and the Ile209 side-chain, would be transmitted to the histidine kinase domain. Interaction between the iron-bound O(2) and Ile209 was also observed in the resonance Raman spectra of RmFixLH as evidenced by the fact that the Fe-O(2) and Fe-CN stretching frequencies were shifted from 575 to 570 cm(-1) (Fe-O(2)), and 504 to 499 cm(-1), respectively, as the result of the replacement of Ile209 with an Ala residue. In the I209A mutant of RmFixL, the O(2) sensing activity was destroyed, thus confirming our proposed mechanism.

PubMed: 10926518
DOI: 10.1006/jmbi.2000.3954

実験手法

X-RAY DIFFRACTION (1.4 Å)