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Structural studies of the Enterococcus faecalis SufU [Fe-S] cluster protein

BACKGROUND: Iron-sulfur clusters are ubiquitous and evolutionarily ancient inorganic prosthetic groups, the biosynthesis of which depends on complex protein machineries. Three distinct assembly systems involved in the maturation of cellular Fe-S proteins have been determined, designated the NIF, ISC...

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Autores principales: Riboldi, Gustavo P, Verli, Hugo, Frazzon, Jeverson
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2009
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2644719/
https://www.ncbi.nlm.nih.gov/pubmed/19187533
http://dx.doi.org/10.1186/1471-2091-10-3
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author Riboldi, Gustavo P
Verli, Hugo
Frazzon, Jeverson
author_facet Riboldi, Gustavo P
Verli, Hugo
Frazzon, Jeverson
author_sort Riboldi, Gustavo P
collection PubMed
description BACKGROUND: Iron-sulfur clusters are ubiquitous and evolutionarily ancient inorganic prosthetic groups, the biosynthesis of which depends on complex protein machineries. Three distinct assembly systems involved in the maturation of cellular Fe-S proteins have been determined, designated the NIF, ISC and SUF systems. Although well described in several organisms, these machineries are poorly understood in Gram-positive bacteria. Within the Firmicutes phylum, the Enterococcus spp. genus have recently assumed importance in clinical microbiology being considered as emerging pathogens for humans, wherein Enterococcus faecalis represents the major species associated with nosocomial infections. The aim of this study was to carry out a phylogenetic analysis in Enterococcus faecalis V583 and a structural and conformational characterisation of it SufU protein. RESULTS: BLAST searches of the Enterococcus genome revealed a series of genes with sequence similarity to the Escherichia coli SUF machinery of [Fe-S] cluster biosynthesis, namely sufB, sufC, sufD and SufS. In addition, the E. coli IscU ortholog SufU was found to be the scaffold protein of Enterococcus spp., containing all features considered essential for its biological activity, including conserved amino acid residues involved in substrate and/or co-factor binding (Cys(50,76,138 )and Asp(52)) and, phylogenetic analyses showed a close relationship with orthologues from other Gram-positive bacteria. Molecular dynamics for structural determinations and molecular modeling using E. faecalis SufU primary sequence protein over the PDB:1su0 crystallographic model from Streptococcus pyogenes were carried out with a subsequent 50 ns molecular dynamic trajectory. This presented a stable model, showing secondary structure modifications near the active site and conserved cysteine residues. Molecular modeling using Haemophilus influenzae IscU primary sequence over the PDB:1su0 crystal followed by a MD trajectory was performed to analyse differences in the C-terminus region of Gram-positive SufU and Gram-negative orthologous proteins, in which several modifications in secondary structure were observed. CONCLUSION: The data describe the identification of the SUF machinery for [Fe-S] cluster biosynthesis present in the Firmicutes genome, showing conserved sufB, sufC, sufD and sufS genes and the presence of the sufU gene coding for scaffold protein, instead of sufA; neither sufE nor sufR are present. Primary sequences and structural analysis of the SufU protein demonstrated its structural-like pattern to the scaffold protein IscU nearby on the ISC machinery. E. faecalis SufU molecular modeling showed high flexibility over the active site regions, and demonstrated the existence of a specific region in Firmicutes denoting the Gram positive region (GPR), suggested as a possible candidate for interaction with other factors and/or regulators.
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spelling pubmed-26447192009-02-19 Structural studies of the Enterococcus faecalis SufU [Fe-S] cluster protein Riboldi, Gustavo P Verli, Hugo Frazzon, Jeverson BMC Biochem Research Article BACKGROUND: Iron-sulfur clusters are ubiquitous and evolutionarily ancient inorganic prosthetic groups, the biosynthesis of which depends on complex protein machineries. Three distinct assembly systems involved in the maturation of cellular Fe-S proteins have been determined, designated the NIF, ISC and SUF systems. Although well described in several organisms, these machineries are poorly understood in Gram-positive bacteria. Within the Firmicutes phylum, the Enterococcus spp. genus have recently assumed importance in clinical microbiology being considered as emerging pathogens for humans, wherein Enterococcus faecalis represents the major species associated with nosocomial infections. The aim of this study was to carry out a phylogenetic analysis in Enterococcus faecalis V583 and a structural and conformational characterisation of it SufU protein. RESULTS: BLAST searches of the Enterococcus genome revealed a series of genes with sequence similarity to the Escherichia coli SUF machinery of [Fe-S] cluster biosynthesis, namely sufB, sufC, sufD and SufS. In addition, the E. coli IscU ortholog SufU was found to be the scaffold protein of Enterococcus spp., containing all features considered essential for its biological activity, including conserved amino acid residues involved in substrate and/or co-factor binding (Cys(50,76,138 )and Asp(52)) and, phylogenetic analyses showed a close relationship with orthologues from other Gram-positive bacteria. Molecular dynamics for structural determinations and molecular modeling using E. faecalis SufU primary sequence protein over the PDB:1su0 crystallographic model from Streptococcus pyogenes were carried out with a subsequent 50 ns molecular dynamic trajectory. This presented a stable model, showing secondary structure modifications near the active site and conserved cysteine residues. Molecular modeling using Haemophilus influenzae IscU primary sequence over the PDB:1su0 crystal followed by a MD trajectory was performed to analyse differences in the C-terminus region of Gram-positive SufU and Gram-negative orthologous proteins, in which several modifications in secondary structure were observed. CONCLUSION: The data describe the identification of the SUF machinery for [Fe-S] cluster biosynthesis present in the Firmicutes genome, showing conserved sufB, sufC, sufD and sufS genes and the presence of the sufU gene coding for scaffold protein, instead of sufA; neither sufE nor sufR are present. Primary sequences and structural analysis of the SufU protein demonstrated its structural-like pattern to the scaffold protein IscU nearby on the ISC machinery. E. faecalis SufU molecular modeling showed high flexibility over the active site regions, and demonstrated the existence of a specific region in Firmicutes denoting the Gram positive region (GPR), suggested as a possible candidate for interaction with other factors and/or regulators. BioMed Central 2009-02-02 /pmc/articles/PMC2644719/ /pubmed/19187533 http://dx.doi.org/10.1186/1471-2091-10-3 Text en Copyright © 2009 Riboldi et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( (http://creativecommons.org/licenses/by/2.0) ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Riboldi, Gustavo P
Verli, Hugo
Frazzon, Jeverson
Structural studies of the Enterococcus faecalis SufU [Fe-S] cluster protein
title Structural studies of the Enterococcus faecalis SufU [Fe-S] cluster protein
title_full Structural studies of the Enterococcus faecalis SufU [Fe-S] cluster protein
title_fullStr Structural studies of the Enterococcus faecalis SufU [Fe-S] cluster protein
title_full_unstemmed Structural studies of the Enterococcus faecalis SufU [Fe-S] cluster protein
title_short Structural studies of the Enterococcus faecalis SufU [Fe-S] cluster protein
title_sort structural studies of the enterococcus faecalis sufu [fe-s] cluster protein
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2644719/
https://www.ncbi.nlm.nih.gov/pubmed/19187533
http://dx.doi.org/10.1186/1471-2091-10-3
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