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 language | English |
|---|---|
| Article number | 110718 |
| Journal | Journal of Inorganic Biochemistry |
| Volume | 198 |
| DOIs | |
| Publication status | Published - 1 Sep 2019 |
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Keywords
- Geobacter
- Multiheme cytochrome
- NMR
- Paramagnetic systems
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Determination of the magnetic properties and orientation of the heme axial ligands of PpcA from Geobacter metallireducens by paramagnetic NMR. / Fernandes, Tomás M.; Morgado, Leonor; Salgueiro, Carlos A.; Turner, David L.
In: Journal of Inorganic Biochemistry, Vol. 198, 110718, 01.09.2019.Research output: Contribution to journal › Article
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
UR - http://www.scopus.com/inward/record.url?scp=85066288346&partnerID=8YFLogxK
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 -