Determination of the magnetic properties and orientation of the heme axial ligands of PpcA from Geobacter metallireducens by paramagnetic NMR

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Abstract

The rising interest in the use of Geobacter bacteria for biotechnological applications demands a deep understanding of how these bacteria are able to thrive in a variety of environments and perform extracellular electron transfer. The Geobacter metallireducens bacterium can couple the oxidation of a wide range of compounds to the reduction of several extracellular acceptors, including heavy metals, toxic organic compounds or electrode surfaces. The periplasmic c-type cytochrome PpcA from this bacterium is a member of a family composed of five periplasmic triheme cytochromes, which are important to bridge the electron transfer between the cytoplasm and the extracellular environment. To better understand the functional mechanism of PpcA it is essential to obtain structural data for this cytochrome. In this work, the geometry of the heme axial ligands, as well as the magnetic properties of the hemes were determined for the oxidized form of the cytochrome, using the 13C NMR chemical shifts of the heme α-substituents. The results were further compared with those previously obtained for the homologous cytochrome from Geobacter sulfurreducens. The orientations of the axial histidine planes and the magnetic properties of the hemes are conserved in both proteins. Overall, the results obtained allowed the definition of the orientation of the magnetic axes of PpcA from G. metallireducens, which will be used as constraints to assist the solution structure determination of the cytochrome in the oxidized form.

Original languageEnglish
Article number110718
JournalJournal of Inorganic Biochemistry
Volume198
DOIs
Publication statusPublished - 1 Sep 2019

Fingerprint

Geobacter
Cytochromes
Heme
Magnetic properties
Nuclear magnetic resonance
Ligands
Bacteria
Cytochrome c Group
Electrons
Poisons
Chemical shift
Heavy Metals
Organic compounds
Histidine
Electrodes
Cytoplasm
5'-deoxy-5'-phosphonomethyladenosine phosphate
Oxidation
Geometry
Proteins

Keywords

  • Geobacter
  • Multiheme cytochrome
  • NMR
  • Paramagnetic systems

Cite this

@article{33cd00d06f1e4b43908f381783abe186,
title = "Determination of the magnetic properties and orientation of the heme axial ligands of PpcA from Geobacter metallireducens by paramagnetic NMR",
abstract = "The rising interest in the use of Geobacter bacteria for biotechnological applications demands a deep understanding of how these bacteria are able to thrive in a variety of environments and perform extracellular electron transfer. The Geobacter metallireducens bacterium can couple the oxidation of a wide range of compounds to the reduction of several extracellular acceptors, including heavy metals, toxic organic compounds or electrode surfaces. The periplasmic c-type cytochrome PpcA from this bacterium is a member of a family composed of five periplasmic triheme cytochromes, which are important to bridge the electron transfer between the cytoplasm and the extracellular environment. To better understand the functional mechanism of PpcA it is essential to obtain structural data for this cytochrome. In this work, the geometry of the heme axial ligands, as well as the magnetic properties of the hemes were determined for the oxidized form of the cytochrome, using the 13C NMR chemical shifts of the heme α-substituents. The results were further compared with those previously obtained for the homologous cytochrome from Geobacter sulfurreducens. The orientations of the axial histidine planes and the magnetic properties of the hemes are conserved in both proteins. Overall, the results obtained allowed the definition of the orientation of the magnetic axes of PpcA from G. metallireducens, which will be used as constraints to assist the solution structure determination of the cytochrome in the oxidized form.",
keywords = "Geobacter, Multiheme cytochrome, NMR, Paramagnetic systems",
author = "Fernandes, {Tom{\'a}s M.} and Leonor Morgado and Salgueiro, {Carlos A.} and Turner, {David L.}",
note = "Fundacao para a Ciencia e Tecnologia (FCT) through the following grants: SFRH/BPD/114848/2016 (to LM), PTDC/BBB-BQB/3554/2014, PTDC/BBB-BQB/4178/2014 and PTDC/BIA-BQM/31981/2017 (to CAS). Applied Molecular Biosciences Unit-UCIBIO which is financed by national funds from FCT/MEC (UID/Multi/04378/2019). The NMR spectrometers are part of Rede Nacional de RMN (PTNMR), supported by FCT-MCTES (ROTEIRO/0031/2013 - PINFRA/22161/2016) co-funded by FEDER through COMPETE 2020, POCI, and PORL and FCT through PIDDAC.",
year = "2019",
month = "9",
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doi = "10.1016/j.jinorgbio.2019.110718",
language = "English",
volume = "198",
journal = "Journal of Inorganic Biochemistry",
issn = "0162-0134",
publisher = "Elsevier Inc.",

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TY - JOUR

T1 - Determination of the magnetic properties and orientation of the heme axial ligands of PpcA from Geobacter metallireducens by paramagnetic NMR

AU - Fernandes, Tomás M.

AU - Morgado, Leonor

AU - Salgueiro, Carlos A.

AU - Turner, David L.

N1 - Fundacao para a Ciencia e Tecnologia (FCT) through the following grants: SFRH/BPD/114848/2016 (to LM), PTDC/BBB-BQB/3554/2014, PTDC/BBB-BQB/4178/2014 and PTDC/BIA-BQM/31981/2017 (to CAS). Applied Molecular Biosciences Unit-UCIBIO which is financed by national funds from FCT/MEC (UID/Multi/04378/2019). The NMR spectrometers are part of Rede Nacional de RMN (PTNMR), supported by FCT-MCTES (ROTEIRO/0031/2013 - PINFRA/22161/2016) co-funded by FEDER through COMPETE 2020, POCI, and PORL and FCT through PIDDAC.

PY - 2019/9/1

Y1 - 2019/9/1

N2 - The rising interest in the use of Geobacter bacteria for biotechnological applications demands a deep understanding of how these bacteria are able to thrive in a variety of environments and perform extracellular electron transfer. The Geobacter metallireducens bacterium can couple the oxidation of a wide range of compounds to the reduction of several extracellular acceptors, including heavy metals, toxic organic compounds or electrode surfaces. The periplasmic c-type cytochrome PpcA from this bacterium is a member of a family composed of five periplasmic triheme cytochromes, which are important to bridge the electron transfer between the cytoplasm and the extracellular environment. To better understand the functional mechanism of PpcA it is essential to obtain structural data for this cytochrome. In this work, the geometry of the heme axial ligands, as well as the magnetic properties of the hemes were determined for the oxidized form of the cytochrome, using the 13C NMR chemical shifts of the heme α-substituents. The results were further compared with those previously obtained for the homologous cytochrome from Geobacter sulfurreducens. The orientations of the axial histidine planes and the magnetic properties of the hemes are conserved in both proteins. Overall, the results obtained allowed the definition of the orientation of the magnetic axes of PpcA from G. metallireducens, which will be used as constraints to assist the solution structure determination of the cytochrome in the oxidized form.

AB - The rising interest in the use of Geobacter bacteria for biotechnological applications demands a deep understanding of how these bacteria are able to thrive in a variety of environments and perform extracellular electron transfer. The Geobacter metallireducens bacterium can couple the oxidation of a wide range of compounds to the reduction of several extracellular acceptors, including heavy metals, toxic organic compounds or electrode surfaces. The periplasmic c-type cytochrome PpcA from this bacterium is a member of a family composed of five periplasmic triheme cytochromes, which are important to bridge the electron transfer between the cytoplasm and the extracellular environment. To better understand the functional mechanism of PpcA it is essential to obtain structural data for this cytochrome. In this work, the geometry of the heme axial ligands, as well as the magnetic properties of the hemes were determined for the oxidized form of the cytochrome, using the 13C NMR chemical shifts of the heme α-substituents. The results were further compared with those previously obtained for the homologous cytochrome from Geobacter sulfurreducens. The orientations of the axial histidine planes and the magnetic properties of the hemes are conserved in both proteins. Overall, the results obtained allowed the definition of the orientation of the magnetic axes of PpcA from G. metallireducens, which will be used as constraints to assist the solution structure determination of the cytochrome in the oxidized form.

KW - Geobacter

KW - Multiheme cytochrome

KW - NMR

KW - Paramagnetic systems

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U2 - 10.1016/j.jinorgbio.2019.110718

DO - 10.1016/j.jinorgbio.2019.110718

M3 - Article

VL - 198

JO - Journal of Inorganic Biochemistry

JF - Journal of Inorganic Biochemistry

SN - 0162-0134

M1 - 110718

ER -