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 language | English |
|---|---|
| Pages (from-to) | 10221-10233 |
| Number of pages | 13 |
| Journal | Journal of Physical Chemistry B |
| Volume | 120 |
| Issue number | 39 |
| DOIs | |
| Publication status | Published - 6 Oct 2016 |
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Unveiling the Structural Basis That Regulates the Energy Transduction Properties within a Family of Triheme Cytochromes from Geobacter sulfurreducens. / Dantas, Joana M.; Simões, Telma; Morgado, Leonor; Caciones, Clara; Fernandes, Ana P.; Silva, Marta A.; Bruix, Marta; Pokkuluri, P. Raj; Salgueiro, Carlos A.
In: Journal of Physical Chemistry B, Vol. 120, No. 39, 06.10.2016, p. 10221-10233.Research output: Contribution to journal › Article
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.
UR - http://www.scopus.com/inward/record.url?scp=84990828215&partnerID=8YFLogxK
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 -