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Chino M, Di Costanzo LF, Leone L, La Gatta S, Famulari A, Chiesa M, Lombardi A, Pavone V. Designed Rubredoxin miniature in a fully artificial electron chain triggered by visible light. Nat Commun 2023; 14:2368. [PMID: 37185349 PMCID: PMC10130062 DOI: 10.1038/s41467-023-37941-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 04/06/2023] [Indexed: 05/17/2023] Open
Abstract
Designing metal sites into de novo proteins has significantly improved, recently. However, identifying the minimal coordination spheres, able to encompass the necessary information for metal binding and activity, still represents a great challenge, today. Here, we test our understanding with a benchmark, nevertheless difficult, case. We assemble into a miniature 28-residue protein, the quintessential elements required to fold properly around a FeCys4 redox center, and to function efficiently in electron-transfer. This study addresses a challenge in de novo protein design, as it reports the crystal structure of a designed tetra-thiolate metal-binding protein in sub-Å agreement with the intended design. This allows us to well correlate structure to spectroscopic and electrochemical properties. Given its high reduction potential compared to natural and designed FeCys4-containing proteins, we exploit it as terminal electron acceptor of a fully artificial chain triggered by visible light.
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Affiliation(s)
- Marco Chino
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, 80126, Napoli, Italy
| | - Luigi Franklin Di Costanzo
- Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, 80055, Portici, Italy
| | - Linda Leone
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, 80126, Napoli, Italy
| | - Salvatore La Gatta
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, 80126, Napoli, Italy
| | - Antonino Famulari
- Department of Chemistry, University of Torino, Via Giuria 9, 10125, Torino, Italy
- Department of Condensed Matter Physics, University of Zaragoza, Calle Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Mario Chiesa
- Department of Chemistry, University of Torino, Via Giuria 9, 10125, Torino, Italy
| | - Angela Lombardi
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, 80126, Napoli, Italy.
| | - Vincenzo Pavone
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 21, 80126, Napoli, Italy.
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Deciphering Molecular Factors That Affect Electron Transfer at the Cell Surface of Electroactive Bacteria: The Case of OmcA from Shewanella oneidensis MR-1. Microorganisms 2022; 11:microorganisms11010079. [PMID: 36677373 PMCID: PMC9861303 DOI: 10.3390/microorganisms11010079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/23/2022] [Accepted: 12/24/2022] [Indexed: 12/29/2022] Open
Abstract
Multiheme cytochromes play a central role in extracellular electron transfer, a process that allows microorganisms to sustain their metabolism with external electron acceptors or donors. In Shewanella oneidensis MR-1, the decaheme cytochromes OmcA and MtrC show functional specificity for interaction with soluble and insoluble redox partners. In this work, the capacity of extracellular electron transfer by mutant variants of S. oneidensis MR-1 OmcA was investigated. The results show that amino acid mutations can affect protein stability and alter the redox properties of the protein, without affecting the ability to perform extracellular electron transfer to methyl orange dye or a poised electrode. The results also show that there is a good correlation between the reduction of the dye and the current generated at the electrode for most but not all mutants. This observation opens the door for investigations of the molecular mechanisms of interaction with different electron acceptors to tailor these surface exposed cytochromes towards specific bio-based applications.
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Campbell IJ, Atkinson JT, Carpenter MD, Myerscough D, Su L, Ajo-Franklin CM, Silberg JJ. Determinants of Multiheme Cytochrome Extracellular Electron Transfer Uncovered by Systematic Peptide Insertion. Biochemistry 2022; 61:1337-1350. [PMID: 35687533 DOI: 10.1021/acs.biochem.2c00148] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The multiheme cytochrome MtrA enables microbial respiration by transferring electrons across the outer membrane to extracellular electron acceptors. While structural studies have identified residues that mediate the binding of MtrA to hemes and to other cytochromes that facilitate extracellular electron transfer (EET), the relative importance of these interactions for EET is not known. To better understand EET, we evaluated how insertion of an octapeptide across all MtrA backbone locations affects Shewanella oneidensis MR-1 respiration on Fe(III). The EET efficiency was found to be inversely correlated with the proximity of the insertion to the heme prosthetic groups. Mutants with decreased EET efficiencies also arose from insertions in a subset of the regions that make residue-residue contacts with the porin MtrB, while all sites contacting the extracellular cytochrome MtrC presented high peptide insertion tolerance. MtrA variants having peptide insertions within the CXXCH motifs that coordinate heme cofactors retained some ability to support respiration on Fe(III), although these variants presented significantly decreased EET efficiencies. Furthermore, the fitness of cells expressing different MtrA variants under Fe(III) respiration conditions correlated with anode reduction. The peptide insertion profile, which represents the first comprehensive sequence-structure-function map for a multiheme cytochrome, implicates MtrA as a strategic protein engineering target for the regulation of EET.
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Affiliation(s)
- Ian J Campbell
- Department of BioSciences, Rice University, 6100 Main Street, MS-140, Houston, Texas 77005, United States
| | - Joshua T Atkinson
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
| | - Matthew D Carpenter
- Department of BioSciences, Rice University, 6100 Main Street, MS-140, Houston, Texas 77005, United States
| | - Dru Myerscough
- Department of BioSciences, Rice University, 6100 Main Street, MS-140, Houston, Texas 77005, United States
| | - Lin Su
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Caroline M Ajo-Franklin
- Department of BioSciences, Rice University, 6100 Main Street, MS-140, Houston, Texas 77005, United States.,Department of Bioengineering, Rice University, 6100 Main Street, MS-142, Houston, Texas 77005, United States
| | - Jonathan J Silberg
- Department of BioSciences, Rice University, 6100 Main Street, MS-140, Houston, Texas 77005, United States.,Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, MS-362, Houston, Texas 77005, United States.,Department of Bioengineering, Rice University, 6100 Main Street, MS-142, Houston, Texas 77005, United States
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Silva AV, Firmino MO, Costa NL, Louro RO, Paquete CM. Investigation of the Molecular Mechanisms of the Eukaryotic Cytochrome-c Maturation System. Biomolecules 2022; 12:biom12040549. [PMID: 35454139 PMCID: PMC9028165 DOI: 10.3390/biom12040549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 02/01/2023] Open
Abstract
Cytochromes-c are ubiquitous heme proteins with enormous impact at the cellular level, being key players in metabolic processes such as electron transfer chains and apoptosis. The assembly of these proteins requires maturation systems that catalyse the formation of the covalent thioether bond between two cysteine residues and the vinyl groups of the heme. System III is the maturation system present in Eukaryotes, designated CcHL or HCCS. This System requires a specific amino acid sequence in the apocytochrome to be recognized as a substrate and for heme insertion. To explore the recognition mechanisms of CcHL, the bacterial tetraheme cytochrome STC from Shewanella oneidensis MR-1, which is not a native substrate for System III, was mutated to be identified as a substrate. The results obtained show that it is possible to convert a bacterial cytochrome as a substrate by CcHL, but the presence of the recognition sequence is not the only factor that induces the maturation of a holocytochrome by System III. The location of this sequence in the polypeptide also plays a role in the maturation of the c-type cytochrome. Furthermore, CcHL appears to be able to catalyse the binding of only one heme per polypeptide chain, being unable to assemble multiheme cytochromes c, in contrast with bacterial maturation systems.
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Kuchenbuch A, Frank R, Ramos JV, Jahnke HG, Harnisch F. Electrochemical Microwell Plate to Study Electroactive Microorganisms in Parallel and Real-Time. Front Bioeng Biotechnol 2022; 9:821734. [PMID: 35242754 PMCID: PMC8887713 DOI: 10.3389/fbioe.2021.821734] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 12/28/2021] [Indexed: 11/26/2022] Open
Abstract
Microbial resource mining of electroactive microorganism (EAM) is currently methodically hampered due to unavailable electrochemical screening tools. Here, we introduce an electrochemical microwell plate (ec-MP) composed of a 96 electrochemical deepwell plate and a recently developed 96-channel multipotentiostat. Using the ec-MP we investigated the electrochemical and metabolic properties of the EAM models Shewanella oneidensis and Geobacter sulfurreducens with acetate and lactate as electron donor combined with an individual genetic analysis of each well. Electrochemical cultivation of pure cultures achieved maximum current densities (j max) and coulombic efficiencies (CE) that were well in line with literature data. The co-cultivation of S. oneidensis and G. sulfurreducens led to an increased current density of j max of 88.57 ± 14.04 µA cm-2 (lactate) and j max of 99.36 ± 19.12 µA cm-2 (lactate and acetate). Further, a decreased time period of reaching j max and biphasic current production was revealed and the microbial electrochemical performance could be linked to the shift in the relative abundance.
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Affiliation(s)
- Anne Kuchenbuch
- Department of Environmental Microbiology, UFZ—Helmholtz-Centre for Environmental Research GmbH, Leipzig, Germany
| | - Ronny Frank
- Centre for Biotechnology and Biomedicine, Molecular Biological-Biochemical Processing Technology, Leipzig University, Leipzig, Germany
| | - José Vazquez Ramos
- Centre for Biotechnology and Biomedicine, Molecular Biological-Biochemical Processing Technology, Leipzig University, Leipzig, Germany
| | - Heinz-Georg Jahnke
- Centre for Biotechnology and Biomedicine, Molecular Biological-Biochemical Processing Technology, Leipzig University, Leipzig, Germany
| | - Falk Harnisch
- Department of Environmental Microbiology, UFZ—Helmholtz-Centre for Environmental Research GmbH, Leipzig, Germany
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Lai D, Khan FST, Rath SP. Multiheme proteins: effect of heme–heme interactions. Dalton Trans 2018; 47:14388-14401. [DOI: 10.1039/c8dt00518d] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
This Frontier illustrates a brief personal account on the effect of heme–heme interactions in dihemes which thereby discloses some of the evolutionary design principles involved in multiheme proteins for their diverse structures and functions.
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Affiliation(s)
- Dipti Lai
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
| | | | - Sankar Prasad Rath
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
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