1DP9

CRYSTAL STRUCTURE OF IMIDAZOLE-BOUND FIXL HEME DOMAIN

Summary for 1DP9

• Entry DOI: 10.2210/pdb1dp9/pdb
• Related: 1BV5 1BV6 1DP6 1DP8
• Descriptor: FIXL PROTEIN, IMIDAZOLE, PROTOPORPHYRIN IX CONTAINING FE, ... (4 entities in total)
• Functional Keywords: heme, fixl heme domain liganded structure, pas domain family, two component system, histidine kinase, oxygen storage-transport complex, oxygen storage/transport
• Biological source: Bradyrhizobium japonicum
• Total number of polymer chains: 1
• Total formula weight: 15605.43

Authors

Gong, W.,Hao, B.,Chan, M.K. (deposition date: 1999-12-24, release date: 2000-12-24, Last modification date: 2024-02-07)

Primary citation

Gong, W.,Hao, B.,Chan, M.K.
New mechanistic insights from structural studies of the oxygen-sensing domain of Bradyrhizobium japonicum FixL.
Biochemistry, 39:3955-3962, 2000

PubMed Abstract: The FixL heme domain serves as the dioxygen switch in the FixL/FixJ two-component system of Rhizobia. Recent structural studies of the Bradyrhizobium japonicum FixL heme domain (BjFixLH) have suggested an allosteric mechanism that is distinct from the classical hemoglobin model. To gain further insight into the FixL sensing mechanism, structures of BjFixLH bound to dioxygen, imidazole, and nitric oxide have been determined. These structures, particularly the structure of BjFixLH bound to its physiological ligand, dioxygen, have helped to address a number of important issues relevant to the BjFixLH sensing mechanism. On the basis of the oxy-BjFixLH structure, a conserved arginine is found to stabilize the dioxygen ligand in a mode reminiscent of the distal histidine in classical myoglobins and hemoglobins. The structure of BjFixLH bound to imidazole elucidates the structural requirements for accommodating sterically bulky ligands. Finally, the structure of BjFixLH bound to nitric oxide provides evidence for a structural intermediate in the heme-driven conformational change.

PubMed: 10747783
DOI: 10.1021/bi992346w

Experimental method

X-RAY DIFFRACTION (2.6 Å)