Spectral characterization of a novel NO sensing protein in bacteria: NosP
| Autor: | Yilin Liu, Elizabeth M. Boon, James R. Kincaid, Bezalel Bacon |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
inorganic chemicals
0301 basic medicine Hemeproteins Hemeprotein Stereochemistry Iron 010402 general chemistry medicine.disease_cause Nitric Oxide 01 natural sciences Biochemistry Cofactor Article Ferrous Legionella pneumophila 03 medical and health sciences chemistry.chemical_compound Bacterial Proteins medicine Heme Vibrio cholerae Binding Sites biology Quorum Sensing biology.organism_classification 0104 chemical sciences Quorum sensing 030104 developmental biology chemistry Pseudomonas aeruginosa biology.protein Ferric Bacteria medicine.drug |
| Popis: | A novel family of bacterial hemoproteins named NosP has been discovered recently; its members are proposed to function as nitric oxide (NO) responsive proteins involved in bacterial group behaviors such as quorum sensing and biofilm growth and dispersal. Currently, little is known about molecular activation mechanisms in NosP. Here, functional studies were performed utilizing the distinct spectroscopic characteristics associated with the NosP heme cofactor. NosPs from Pseudomonas aeruginosa (Pa), Vibrio cholerae (Vc) and Legionella pneumophila (Lpg) were studied in their ferrous-unligated forms as well as their ferrous-CO, ferrous-NO, and ferric-CN adducts. The resonance Raman (rR) data collected on the ferric forms strongly support the existence of a distorted heme-cofactor, which is a common feature in NO sensors. The ferrous spectra exhibit a 213 cm−1 feature, which is assigned to the Fe-Nhis stretching mode. The Fe-C and C-O frequencies in the spectra of ferrous-CO NosP complexes are inversely correlated with relatively similar frequencies, consistent with a proximal histidine ligand and a relatively hydrophobic environment. The rR spectra obtained for isotopically labeled ferrous-NO adducts provide evidence of formation of a 5-coordinate NO complex, resulting from proximal Fe-Nhis cleavage, which is believed to play a role in biological heme-NO signal transduction. Additionally, we found that of the three NosPs studied, Lpg NosP contains the most electropositive ligand binding pocket, while Pa NosP has the most electronegative ligand binding pocket. This pattern is also observed in the measured heme reduction potentials for these three proteins, which may indicate distinct functions for each. |
| Databáze: | OpenAIRE |
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