6CEQ

The Aer2 Receptor from Vibrio cholerae is a Dual PAS-Heme Oxygen Sensor

Summary for 6CEQ

• Entry DOI: 10.2210/pdb6ceq/pdb
• Descriptor: Methyl-accepting chemotaxis protein, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• Functional Keywords: pas domain, vibrio cholera, chemoreceptor, heme, signal transduction, signaling protein
• Biological source: Vibrio cholerae
• Total number of polymer chains: 3
• Total formula weight: 38813.37

Authors

Crane, B.R.,Chua, T.K.,Sukomon, N. (deposition date: 2018-02-12, release date: 2018-05-16, Last modification date: 2024-03-13)

Primary citation

Greer-Phillips, S.E.,Sukomon, N.,Chua, T.K.,Johnson, M.S.,Crane, B.R.,Watts, K.J.
THE AER2 RECEPTOR FROM VIBRIO CHOLERAE IS A DUAL PAS-HEME OXYGEN SENSOR.
Mol. Microbiol., 2018

PubMed Abstract: The diarrheal pathogen Vibrio cholerae navigates complex environments using three chemosensory systems and 44-45 chemoreceptors. Chemosensory cluster II modulates chemotaxis, whereas clusters I and III have unknown functions. Ligands have been identified for only five V. cholerae chemoreceptors. Here, we report that the cluster III receptor, VcAer2, binds and responds to O . VcAer2 is an ortholog of Pseudomonas aeruginosa Aer2 (PaAer2) but differs in that VcAer2 has two, rather than one, N-terminal PAS domain. We have determined that both PAS1 and PAS2 form homodimers and bind penta-coordinate b-type heme via an Eη-His residue. Heme binding to PAS1 required the entire PAS core, but receptor function also required the N-terminal cap. PAS2 functioned as an O -sensor [ , 19 μM], utilizing the same Iβ Trp (W276) as PaAer2 to stabilize O . The crystal structure of PAS2-W276L was similar to that of PaAer2-PAS but resided in an active conformation mimicking the ligand-bound state, consistent with its signal-on phenotype. PAS1 also bound O [ , 12 μM], although O binding was stabilized by either a Trp residue or Tyr residue. Moreover, PAS1 appeared to function as a signal modulator, regulating O -mediated signaling from PAS2 and resulting in activation of the cluster III chemosensory pathway.

PubMed: 29719085
DOI: 10.1111/mmi.13978

Experimental method

X-RAY DIFFRACTION (1.67 Å)