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Crystallographic and molecular dynamics simulation analysis of Escherichia coli dihydroneopterin aldolase
BACKGROUND: Dihydroneopterin aldolase (DHNA) catalyzes the conversion of 7,8-dihydroneopterin to 6-hydroxymethyl-7,8-dihydropterin and also the epimerization of DHNP to 7,8-dihydromonapterin. Previously, we determined the crystal structure of Staphylococcus aureus DHNA (SaDHNA) in complex with the s...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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BioMed Central
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4176595/ https://www.ncbi.nlm.nih.gov/pubmed/25264482 http://dx.doi.org/10.1186/2045-3701-4-52 |
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author | Blaszczyk, Jaroslaw Lu, Zhenwei Li, Yue Yan, Honggao Ji, Xinhua |
author_facet | Blaszczyk, Jaroslaw Lu, Zhenwei Li, Yue Yan, Honggao Ji, Xinhua |
author_sort | Blaszczyk, Jaroslaw |
collection | PubMed |
description | BACKGROUND: Dihydroneopterin aldolase (DHNA) catalyzes the conversion of 7,8-dihydroneopterin to 6-hydroxymethyl-7,8-dihydropterin and also the epimerization of DHNP to 7,8-dihydromonapterin. Previously, we determined the crystal structure of Staphylococcus aureus DHNA (SaDHNA) in complex with the substrate analogue neopterin (NP). We also showed that Escherichia coli DHNA (EcDHNA) and SaDHNA have significantly different binding and catalytic properties by biochemical analysis. On the basis of these structural and functional data, we proposed a catalytic mechanism involving two proton wires. RESULTS: To understand the structural basis for the biochemical differences and further investigate the catalytic mechanism of DHNA, we have determined the structure of EcDHNA complexed with NP at 1.07-Å resolution [PDB:2O90], built an atomic model of EcDHNA complexed with the substrate DHNP, and performed molecular dynamics (MD) simulation analysis of the substrate complex. EcDHNA has the same fold as SaDHNA and also forms an octamer that consists of two tetramers, but the packing of one tetramer with the other is significantly different between the two enzymes. Furthermore, the structures reveal significant differences in the vicinity of the active site, particularly in the loop that connects strands β3 and β4, mainly due to the substitution of nearby residues. The building of an atomic model of the complex of EcDHNA and the substrate DHNP and the MD simulation of the complex show that some of the hydrogen bonds between the substrate and the enzyme are persistent, whereas others are transient. The substrate binding model and MD simulation provide the molecular basis for the biochemical behaviors of the enzyme, including noncooperative substrate binding, indiscrimination of a pair of epimers as the substrates, proton wire switching during catalysis, and formation of epimerization product. CONCLUSIONS: The EcDHNA and SaDHNA structures, each in complex with NP, reveal the basis for the biochemical differences between EcDHNA and SaDHNA. The atomic substrate binding model and MD simulation offer insights into substrate binding and catalysis by DHNA. The EcDHNA structure also affords an opportunity to develop antimicrobials specific for Gram-negative bacteria, as DHNAs from Gram-negative bacteria are highly homologous and E. coli is a representative of this class of bacteria. |
format | Online Article Text |
id | pubmed-4176595 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-41765952014-09-28 Crystallographic and molecular dynamics simulation analysis of Escherichia coli dihydroneopterin aldolase Blaszczyk, Jaroslaw Lu, Zhenwei Li, Yue Yan, Honggao Ji, Xinhua Cell Biosci Research BACKGROUND: Dihydroneopterin aldolase (DHNA) catalyzes the conversion of 7,8-dihydroneopterin to 6-hydroxymethyl-7,8-dihydropterin and also the epimerization of DHNP to 7,8-dihydromonapterin. Previously, we determined the crystal structure of Staphylococcus aureus DHNA (SaDHNA) in complex with the substrate analogue neopterin (NP). We also showed that Escherichia coli DHNA (EcDHNA) and SaDHNA have significantly different binding and catalytic properties by biochemical analysis. On the basis of these structural and functional data, we proposed a catalytic mechanism involving two proton wires. RESULTS: To understand the structural basis for the biochemical differences and further investigate the catalytic mechanism of DHNA, we have determined the structure of EcDHNA complexed with NP at 1.07-Å resolution [PDB:2O90], built an atomic model of EcDHNA complexed with the substrate DHNP, and performed molecular dynamics (MD) simulation analysis of the substrate complex. EcDHNA has the same fold as SaDHNA and also forms an octamer that consists of two tetramers, but the packing of one tetramer with the other is significantly different between the two enzymes. Furthermore, the structures reveal significant differences in the vicinity of the active site, particularly in the loop that connects strands β3 and β4, mainly due to the substitution of nearby residues. The building of an atomic model of the complex of EcDHNA and the substrate DHNP and the MD simulation of the complex show that some of the hydrogen bonds between the substrate and the enzyme are persistent, whereas others are transient. The substrate binding model and MD simulation provide the molecular basis for the biochemical behaviors of the enzyme, including noncooperative substrate binding, indiscrimination of a pair of epimers as the substrates, proton wire switching during catalysis, and formation of epimerization product. CONCLUSIONS: The EcDHNA and SaDHNA structures, each in complex with NP, reveal the basis for the biochemical differences between EcDHNA and SaDHNA. The atomic substrate binding model and MD simulation offer insights into substrate binding and catalysis by DHNA. The EcDHNA structure also affords an opportunity to develop antimicrobials specific for Gram-negative bacteria, as DHNAs from Gram-negative bacteria are highly homologous and E. coli is a representative of this class of bacteria. BioMed Central 2014-09-02 /pmc/articles/PMC4176595/ /pubmed/25264482 http://dx.doi.org/10.1186/2045-3701-4-52 Text en © Blaszczyk et al.; licensee BioMed Central Ltd. 2014 This article is published under license to BioMed Central Ltd. 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 work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. |
spellingShingle | Research Blaszczyk, Jaroslaw Lu, Zhenwei Li, Yue Yan, Honggao Ji, Xinhua Crystallographic and molecular dynamics simulation analysis of Escherichia coli dihydroneopterin aldolase |
title | Crystallographic and molecular dynamics simulation analysis of Escherichia coli dihydroneopterin aldolase |
title_full | Crystallographic and molecular dynamics simulation analysis of Escherichia coli dihydroneopterin aldolase |
title_fullStr | Crystallographic and molecular dynamics simulation analysis of Escherichia coli dihydroneopterin aldolase |
title_full_unstemmed | Crystallographic and molecular dynamics simulation analysis of Escherichia coli dihydroneopterin aldolase |
title_short | Crystallographic and molecular dynamics simulation analysis of Escherichia coli dihydroneopterin aldolase |
title_sort | crystallographic and molecular dynamics simulation analysis of escherichia coli dihydroneopterin aldolase |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4176595/ https://www.ncbi.nlm.nih.gov/pubmed/25264482 http://dx.doi.org/10.1186/2045-3701-4-52 |
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