Structural insights on the efficient catalysis of hydroperoxide reduction by Ohr: Crystallographic and molecular dynamics approaches

Organic hydroperoxide resistance (Ohr) enzymes are highly efficient Cys-based peroxidases that play central roles in bacterial response to fatty acid hydroperoxides and peroxynitrite, two oxidants that are generated during host-pathogen interactions. In the active site of Ohr proteins, the conserved...

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Autores principales: Piccirillo, Erika, Alegria, Thiago G. P., Discola, Karen F., Cussiol, José R. R., Domingos, Renato M., de Oliveira, Marcos A., de Rezende, Leandro, Netto, Luis E. S., Amaral, Antonia T-do
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2018
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Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5962072/
https://www.ncbi.nlm.nih.gov/pubmed/29782551
http://dx.doi.org/10.1371/journal.pone.0196918
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author Piccirillo, Erika
Alegria, Thiago G. P.
Discola, Karen F.
Cussiol, José R. R.
Domingos, Renato M.
de Oliveira, Marcos A.
de Rezende, Leandro
Netto, Luis E. S.
Amaral, Antonia T-do
author_facet Piccirillo, Erika
Alegria, Thiago G. P.
Discola, Karen F.
Cussiol, José R. R.
Domingos, Renato M.
de Oliveira, Marcos A.
de Rezende, Leandro
Netto, Luis E. S.
Amaral, Antonia T-do
author_sort Piccirillo, Erika
collection PubMed
description Organic hydroperoxide resistance (Ohr) enzymes are highly efficient Cys-based peroxidases that play central roles in bacterial response to fatty acid hydroperoxides and peroxynitrite, two oxidants that are generated during host-pathogen interactions. In the active site of Ohr proteins, the conserved Arg (Arg19 in Ohr from Xylella fastidiosa) and Glu (Glu51 in Ohr from Xylella fastidiosa) residues, among other factors, are involved in the extremely high reactivity of the peroxidatic Cys (C(p)) toward hydroperoxides. In the closed state, the thiolate of C(p) is in close proximity to the guanidinium group of Arg19. Ohr enzymes can also assume an open state, where the loop containing the catalytic Arg is far away from C(p) and Glu51. Here, we aimed to gain insights into the putative structural switches of the Ohr catalytic cycle. First, we describe the crystal structure of Ohr from Xylella fastidiosa (XfOhr) in the open state that, together with the previously described XfOhr structure in the closed state, may represent two snapshots along the coordinate of the enzyme-catalyzed reaction. These two structures were used for the experimental validation of molecular dynamics (MD) simulations. MD simulations employing distinct protonation states and in silico mutagenesis indicated that the polar interactions of Arg19 with Glu51 and C(p) contributed to the stabilization of XfOhr in the closed state. Indeed, C(p) oxidation to the disulfide state facilitated the switching of the Arg19 loop from the closed to the open state. In addition to the Arg19 loop, other portions of XfOhr displayed high mobility, such as a loop rich in Gly residues. In summary, we obtained a high correlation between crystallographic data, MD simulations and biochemical/enzymatic assays. The dynamics of the Ohr enzymes are unique among the Cys-based peroxidases, in which the active site Arg undergoes structural switches throughout the catalytic cycle, while C(p) remains relatively static.
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spelling pubmed-59620722018-06-02 Structural insights on the efficient catalysis of hydroperoxide reduction by Ohr: Crystallographic and molecular dynamics approaches Piccirillo, Erika Alegria, Thiago G. P. Discola, Karen F. Cussiol, José R. R. Domingos, Renato M. de Oliveira, Marcos A. de Rezende, Leandro Netto, Luis E. S. Amaral, Antonia T-do PLoS One Research Article Organic hydroperoxide resistance (Ohr) enzymes are highly efficient Cys-based peroxidases that play central roles in bacterial response to fatty acid hydroperoxides and peroxynitrite, two oxidants that are generated during host-pathogen interactions. In the active site of Ohr proteins, the conserved Arg (Arg19 in Ohr from Xylella fastidiosa) and Glu (Glu51 in Ohr from Xylella fastidiosa) residues, among other factors, are involved in the extremely high reactivity of the peroxidatic Cys (C(p)) toward hydroperoxides. In the closed state, the thiolate of C(p) is in close proximity to the guanidinium group of Arg19. Ohr enzymes can also assume an open state, where the loop containing the catalytic Arg is far away from C(p) and Glu51. Here, we aimed to gain insights into the putative structural switches of the Ohr catalytic cycle. First, we describe the crystal structure of Ohr from Xylella fastidiosa (XfOhr) in the open state that, together with the previously described XfOhr structure in the closed state, may represent two snapshots along the coordinate of the enzyme-catalyzed reaction. These two structures were used for the experimental validation of molecular dynamics (MD) simulations. MD simulations employing distinct protonation states and in silico mutagenesis indicated that the polar interactions of Arg19 with Glu51 and C(p) contributed to the stabilization of XfOhr in the closed state. Indeed, C(p) oxidation to the disulfide state facilitated the switching of the Arg19 loop from the closed to the open state. In addition to the Arg19 loop, other portions of XfOhr displayed high mobility, such as a loop rich in Gly residues. In summary, we obtained a high correlation between crystallographic data, MD simulations and biochemical/enzymatic assays. The dynamics of the Ohr enzymes are unique among the Cys-based peroxidases, in which the active site Arg undergoes structural switches throughout the catalytic cycle, while C(p) remains relatively static. Public Library of Science 2018-05-21 /pmc/articles/PMC5962072/ /pubmed/29782551 http://dx.doi.org/10.1371/journal.pone.0196918 Text en © 2018 Piccirillo et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Piccirillo, Erika
Alegria, Thiago G. P.
Discola, Karen F.
Cussiol, José R. R.
Domingos, Renato M.
de Oliveira, Marcos A.
de Rezende, Leandro
Netto, Luis E. S.
Amaral, Antonia T-do
Structural insights on the efficient catalysis of hydroperoxide reduction by Ohr: Crystallographic and molecular dynamics approaches
title Structural insights on the efficient catalysis of hydroperoxide reduction by Ohr: Crystallographic and molecular dynamics approaches
title_full Structural insights on the efficient catalysis of hydroperoxide reduction by Ohr: Crystallographic and molecular dynamics approaches
title_fullStr Structural insights on the efficient catalysis of hydroperoxide reduction by Ohr: Crystallographic and molecular dynamics approaches
title_full_unstemmed Structural insights on the efficient catalysis of hydroperoxide reduction by Ohr: Crystallographic and molecular dynamics approaches
title_short Structural insights on the efficient catalysis of hydroperoxide reduction by Ohr: Crystallographic and molecular dynamics approaches
title_sort structural insights on the efficient catalysis of hydroperoxide reduction by ohr: crystallographic and molecular dynamics approaches
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5962072/
https://www.ncbi.nlm.nih.gov/pubmed/29782551
http://dx.doi.org/10.1371/journal.pone.0196918
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