Bezalel A Bacon1, Yilin Liu2, James R Kincaid2, Elizabeth M Boon1,3. 1. Graduate program in Biochemistry and Structural Biology , Stony Brook University , Stony Brook , New York 11790-3400 , United States. 2. Department of Chemistry , Marquette University , Milwaukee , Wisconsin 53233 , United States. 3. Department of Chemistry and Institute of Chemical Biology and Drug Discovery , Stony Brook University , Stony Brook , New York 11794-3400 , United States.
Abstract
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.
A novel family of bacterial hemoproteins named NosP has been dispanclass="Chemical">covered recently; its members are proposed to function as class="Species">pan class="Chemical">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 hemecofactor. 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 hemecofactor, 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.
Authors: Charles Olea; Elizabeth M Boon; Patricia Pellicena; John Kuriyan; Michael A Marletta Journal: ACS Chem Biol Date: 2008-11-21 Impact factor: 5.100
Authors: Lisa-Marie Nisbett; Lucas Binnenkade; Bezalel Bacon; Sajjad Hossain; Nicholas J Kotloski; Evan D Brutinel; Raimo Hartmann; Knut Drescher; Dhruv P Arora; Sandhya Muralidharan; Kai M Thormann; Jeffrey A Gralnick; Elizabeth M Boon Journal: Biochemistry Date: 2019-11-18 Impact factor: 3.162