1V9Z

Crystal Structure of the heme PAS sensor domain of Ec DOS (Ferrous Form)

Summary for 1V9Z

• Entry DOI: 10.2210/pdb1v9z/pdb
• Related: 1V9Y
• Descriptor: Heme pas sensor protein, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• Functional Keywords: heme, pas, sensor, signaling protein
• Biological source: Escherichia coli
• Total number of polymer chains: 2
• Total formula weight: 39280.29

Authors

Kurokawa, H.,Lee, D.S.,Watanabe, M.,Sagami, I.,Mikami, B.,Raman, C.S.,Shimizu, T. (deposition date: 2004-02-04, release date: 2004-05-25, Last modification date: 2023-12-27)

Primary citation

Kurokawa, H.,Lee, D.S.,Watanabe, M.,Sagami, I.,Mikami, B.,Raman, C.S.,Shimizu, T.
A redox-controlled molecular switch revealed by the crystal structure of a bacterial heme PAS sensor.
J.Biol.Chem., 279:20186-20193, 2004

PubMed Abstract: PAS domains, which have been identified in over 1100 proteins from all three kingdoms of life, convert various input stimuli into signals that propagate to downstream components by modifying protein-protein interactions. One such protein is the Escherichia coli redox sensor, Ec DOS, a phosphodiesterase that degrades cyclic adenosine monophosphate in a redox-dependent manner. Here we report the crystal structures of the heme PAS domain of Ec DOS in both inactive Fe(3+) and active Fe(2+) forms at 1.32 and 1.9 A resolution, respectively. The protein folds into a characteristic PAS domain structure and forms a homodimer. In the Fe(3+) form, the heme iron is ligated to a His-77 side chain and a water molecule. Heme iron reduction is accompanied by heme-ligand switching from the water molecule to a side chain of Met-95 from the FG loop. Concomitantly, the flexible FG loop is significantly rigidified, along with a change in the hydrogen bonding pattern and rotation of subunits relative to each other. The present data led us to propose a novel redox-regulated molecular switch in which local heme-ligand switching may trigger a global "scissor-type" subunit movement that facilitates catalytic control.

PubMed: 14982921
DOI: 10.1074/jbc.M314199200

Experimental method

X-RAY DIFFRACTION (1.9 Å)