A di-iron protein recruited as an Fe[II] and oxygen sensor for bacterial chemotaxis functions by stabilizing an iron-peroxy species.
Proc Natl Acad Sci U S A
; 116(30): 14955-14960, 2019 07 23.
Article
in En
| MEDLINE
| ID: mdl-31270241
ABSTRACT
Many bacteria contain cytoplasmic chemoreceptors that lack sensor domains. Here, we demonstrate that such cytoplasmic receptors found in 8 different bacterial and archaeal phyla genetically couple to metalloproteins related to ß-lactamases and nitric oxide reductases. We show that this oxygen-binding di-iron protein (ODP) acts as a sensor for chemotactic responses to both iron and oxygen in the human pathogen Treponema denticola (Td). The ODP di-iron site binds oxygen at high affinity to reversibly form an unusually stable µ-peroxo adduct. Crystal structures of ODP from Td and the thermophile Thermotoga maritima (Tm) in the Fe[III]2-O22-, Zn[II], and apo states display differences in subunit association, conformation, and metal coordination that indicate potential mechanisms for sensing. In reconstituted systems, iron-peroxo ODP destabilizes the phosphorylated form of the receptor-coupled histidine kinase CheA, thereby providing a biochemical link between oxygen sensing and chemotaxis in diverse prokaryotes, including anaerobes of ancient origin.
Key words
Full text:
1
Database:
MEDLINE
Main subject:
Oxidoreductases
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Bacterial Proteins
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Signal Transduction
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Chemotaxis
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Iron-Binding Proteins
Language:
En
Year:
2019
Type:
Article