2N91

A key amino acid in the control of different functional behavior within the triheme cytochrome family from Geobacter sulfurreducens

Summary for 2N91

• Entry DOI: 10.2210/pdb2n91/pdb
• Related: 2LDO
• NMR Information: BMRB: 25874
• Descriptor: Cytochrome C, PROTOPORPHYRIN IX CONTAINING FE (2 entities in total)
• Functional Keywords: triheme cytochrome, electron transfer, geobacter, site-directed mutagenesis, redox-bohr, electron transport
• Biological source: Geobacter sulfurreducens
• Total number of polymer chains: 1
• Total formula weight: 9631.63

Authors

Dantas, J.M.,Simoes, T.,Bruix, M.,Salgueiro, C.A. (deposition date: 2015-11-02, release date: 2016-09-21, Last modification date: 2024-05-01)

Primary citation

Dantas, J.M.,Simoes, T.,Morgado, L.,Caciones, C.,Fernandes, A.P.,Silva, M.A.,Bruix, M.,Pokkuluri, P.R.,Salgueiro, C.A.
Unveiling the Structural Basis That Regulates the Energy Transduction Properties within a Family of Triheme Cytochromes from Geobacter sulfurreducens.
J.Phys.Chem.B, 120:10221-10233, 2016

PubMed 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 Leu 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 Phe 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.

PubMed: 27603556
DOI: 10.1021/acs.jpcb.6b07059

Experimental method

SOLUTION NMR