Unveiling the Structural Basis That Regulates the Energy Transduction Properties within a Family of Triheme Cytochromes from Geobacter sulfurreducens

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Abstract

A family of triheme cytochromes from Geobacter sulfurreducens plays an important role in extracellular electron transfer. In addition to their role in electron transfer pathways, two members of this family (PpcA and PpcD) were also found to be able to couple e-/H+ transfer through the redox Bohr effect observed in the physiological pH range, a feature not observed for cytochromes PpcB and PpcE. In attempting to understand the molecular control of the redox Bohr effect in this family of cytochromes, which is highly homologous both in amino acid sequence and structures, it was observed that residue 6 is a conserved leucine in PpcA and PpcD, whereas in the other two characterized members (PpcB and PpcE) the equivalent residue is a phenylalanine. To determine the role of this residue located close to the redox Bohr center, we replaced Leu6 in PpcA with Phe and determined the redox properties of the mutant, as well as its solution structure in the fully reduced state. In contrast with the native form, the mutant PpcAL6F is not able to couple the e-/H+ pathway. We carried out the reverse mutation in PpcB and PpcE (i.e., replacing Phe6 in these two proteins by leucine) and the mutated proteins showed an increased redox Bohr effect. The results clearly establish the role of residue 6 in the control of the redox Bohr effect in this family of cytochromes, a feature that could enable the rational design of G. sulfurreducens strains that carry mutant cytochromes with an optimal redox Bohr effect that would be suitable for various biotechnological applications.

Original languageEnglish
Pages (from-to)10221-10233
Number of pages13
JournalJournal of Physical Chemistry B
Volume120
Issue number39
DOIs
Publication statusPublished - 6 Oct 2016

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cytochromes
Cytochromes
Proteins
leucine
energy
Leucine
electron transfer
Cytochromes a
proteins
phenylalanine
Electrons
mutations
Oxidation-Reduction
Phenylalanine
amino acids
Amino acids
Amino Acids
5'-deoxy-5'-phosphonomethyladenosine phosphate

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@article{fdb330a13dab4d118e744cee346308e2,
title = "Unveiling the Structural Basis That Regulates the Energy Transduction Properties within a Family of Triheme Cytochromes from Geobacter sulfurreducens",
abstract = "A family of triheme cytochromes from Geobacter sulfurreducens plays an important role in extracellular electron transfer. In addition to their role in electron transfer pathways, two members of this family (PpcA and PpcD) were also found to be able to couple e-/H+ transfer through the redox Bohr effect observed in the physiological pH range, a feature not observed for cytochromes PpcB and PpcE. In attempting to understand the molecular control of the redox Bohr effect in this family of cytochromes, which is highly homologous both in amino acid sequence and structures, it was observed that residue 6 is a conserved leucine in PpcA and PpcD, whereas in the other two characterized members (PpcB and PpcE) the equivalent residue is a phenylalanine. To determine the role of this residue located close to the redox Bohr center, we replaced Leu6 in PpcA with Phe and determined the redox properties of the mutant, as well as its solution structure in the fully reduced state. In contrast with the native form, the mutant PpcAL6F is not able to couple the e-/H+ pathway. We carried out the reverse mutation in PpcB and PpcE (i.e., replacing Phe6 in these two proteins by leucine) and the mutated proteins showed an increased redox Bohr effect. The results clearly establish the role of residue 6 in the control of the redox Bohr effect in this family of cytochromes, a feature that could enable the rational design of G. sulfurreducens strains that carry mutant cytochromes with an optimal redox Bohr effect that would be suitable for various biotechnological applications.",
author = "Dantas, {Joana M.} and Telma Sim{\~o}es and Leonor Morgado and Clara Caciones and Fernandes, {Ana P.} and Silva, {Marta A.} and Marta Bruix and Pokkuluri, {P. Raj} and Salgueiro, {Carlos A.}",
note = "info:eu-repo/grantAgreement/FCT/SFRH/SFRH{\%}2FBD{\%}2F89701{\%}2F2012/PT# info:eu-repo/grantAgreement/FCT/SFRH/SFRH{\%}2FBD{\%}2F86439{\%}2F2012/PT# info:eu-repo/grantAgreement/FCT/SFRH/SFRH{\%}2FBD{\%}2F61952{\%}2F2009/PT# info:eu-repo/grantAgreement/FCT/5876/147258/PT# This work was supported by the following project grants: PTDC/BBB-BQB/3554/2014 (to C.A.S.); Fundacao para a Ciencia e a Tecnologia (RECl/BBB-BQB/0230/2012). P.R.P. is partially supported by the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences of the U.S. Department of Energy program under contract no. DE-AC02-06CH11357.",
year = "2016",
month = "10",
day = "6",
doi = "10.1021/acs.jpcb.6b07059",
language = "English",
volume = "120",
pages = "10221--10233",
journal = "Journal of Physical Chemistry B",
issn = "1520-6106",
publisher = "AMER CHEMICAL SOC",
number = "39",

}

TY - JOUR

T1 - Unveiling the Structural Basis That Regulates the Energy Transduction Properties within a Family of Triheme Cytochromes from Geobacter sulfurreducens

AU - Dantas, Joana M.

AU - Simões, Telma

AU - Morgado, Leonor

AU - Caciones, Clara

AU - Fernandes, Ana P.

AU - Silva, Marta A.

AU - Bruix, Marta

AU - Pokkuluri, P. Raj

AU - Salgueiro, Carlos A.

N1 - info:eu-repo/grantAgreement/FCT/SFRH/SFRH%2FBD%2F89701%2F2012/PT# info:eu-repo/grantAgreement/FCT/SFRH/SFRH%2FBD%2F86439%2F2012/PT# info:eu-repo/grantAgreement/FCT/SFRH/SFRH%2FBD%2F61952%2F2009/PT# info:eu-repo/grantAgreement/FCT/5876/147258/PT# This work was supported by the following project grants: PTDC/BBB-BQB/3554/2014 (to C.A.S.); Fundacao para a Ciencia e a Tecnologia (RECl/BBB-BQB/0230/2012). P.R.P. is partially supported by the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences of the U.S. Department of Energy program under contract no. DE-AC02-06CH11357.

PY - 2016/10/6

Y1 - 2016/10/6

N2 - A family of triheme cytochromes from Geobacter sulfurreducens plays an important role in extracellular electron transfer. In addition to their role in electron transfer pathways, two members of this family (PpcA and PpcD) were also found to be able to couple e-/H+ transfer through the redox Bohr effect observed in the physiological pH range, a feature not observed for cytochromes PpcB and PpcE. In attempting to understand the molecular control of the redox Bohr effect in this family of cytochromes, which is highly homologous both in amino acid sequence and structures, it was observed that residue 6 is a conserved leucine in PpcA and PpcD, whereas in the other two characterized members (PpcB and PpcE) the equivalent residue is a phenylalanine. To determine the role of this residue located close to the redox Bohr center, we replaced Leu6 in PpcA with Phe and determined the redox properties of the mutant, as well as its solution structure in the fully reduced state. In contrast with the native form, the mutant PpcAL6F is not able to couple the e-/H+ pathway. We carried out the reverse mutation in PpcB and PpcE (i.e., replacing Phe6 in these two proteins by leucine) and the mutated proteins showed an increased redox Bohr effect. The results clearly establish the role of residue 6 in the control of the redox Bohr effect in this family of cytochromes, a feature that could enable the rational design of G. sulfurreducens strains that carry mutant cytochromes with an optimal redox Bohr effect that would be suitable for various biotechnological applications.

AB - A family of triheme cytochromes from Geobacter sulfurreducens plays an important role in extracellular electron transfer. In addition to their role in electron transfer pathways, two members of this family (PpcA and PpcD) were also found to be able to couple e-/H+ transfer through the redox Bohr effect observed in the physiological pH range, a feature not observed for cytochromes PpcB and PpcE. In attempting to understand the molecular control of the redox Bohr effect in this family of cytochromes, which is highly homologous both in amino acid sequence and structures, it was observed that residue 6 is a conserved leucine in PpcA and PpcD, whereas in the other two characterized members (PpcB and PpcE) the equivalent residue is a phenylalanine. To determine the role of this residue located close to the redox Bohr center, we replaced Leu6 in PpcA with Phe and determined the redox properties of the mutant, as well as its solution structure in the fully reduced state. In contrast with the native form, the mutant PpcAL6F is not able to couple the e-/H+ pathway. We carried out the reverse mutation in PpcB and PpcE (i.e., replacing Phe6 in these two proteins by leucine) and the mutated proteins showed an increased redox Bohr effect. The results clearly establish the role of residue 6 in the control of the redox Bohr effect in this family of cytochromes, a feature that could enable the rational design of G. sulfurreducens strains that carry mutant cytochromes with an optimal redox Bohr effect that would be suitable for various biotechnological applications.

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U2 - 10.1021/acs.jpcb.6b07059

DO - 10.1021/acs.jpcb.6b07059

M3 - Article

VL - 120

SP - 10221

EP - 10233

JO - Journal of Physical Chemistry B

JF - Journal of Physical Chemistry B

SN - 1520-6106

IS - 39

ER -