A cellular selection identifies elongated flavodoxins that support electron transfer to sulfite reductase
Year: 2023
Type: article
Abstract: Flavodoxins (Flds) mediate the flux of electrons between oxidoreductases in diverse metabolic pathways. To investigate whether Flds can support electron transfer to a sulfite reductase (SIR) that evolved to couple with a ferredoxin, we evaluated the ability of Flds to transfer electrons from a ferredoxin-NADP reductase (FNR) to a ferredoxin-dependent SIR using growth complementation of an Escherichia coli strain with a sulfur metabolism defect. We show that Flds from cyanobacteria complement this growth defect when coexpressed with an FNR and an SIR that evolved to couple with a plant ferredoxin. When we evaluated the effect of peptide insertion on Fld-mediated electron transfer, we observed a sensitivity to insertions within regions predicted to be proximal to the cofactor and partner binding sites, while a high insertion tolerance was detected within loops distal from the cofactor and within regions of helices and sheets that are proximal to those loops. Bioinformatic analysis showed that natural Fld sequence variability predicts a large fraction of the motifs that tolerate insertion of the octapeptide SGRPGSLS. These results represent the first evidence that Flds can support electron transfer to assimilatory SIRs, and they suggest that the pattern of insertion tolerance is influenced by interactions with oxidoreductase partners.
Source: Protein Science
DOI: 10.1002/pro.4746
Authors: Albert Truong, Dru Myerscough, Ian Campbell, Joshua Atkinson, Jonathan J. Silberg
Institution: Rice University
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: green
Awards: G1200619422, G1928829289, UNDERSTANDING REDOX PROPORTIONING THROUGH FERREDOXINS, LOW POTENTIAL IRON-SULFUR PROTEINS ACTING AS ELECTRICAL HUBS TO CONTROL METABOLISM, G2382721862, G301926269, NSF Postdoctoral Fellowship in Biology FY 2020, G4534273316, G7452299184, LIFE IS ELECTRIC. THE ELECTRONIC CIRCUITRY IS CATALYZED BY A SMALL SUBSET OF PROTEINS THAT FUNCTION AS SOPHISTICATED NANOMACHINES. CURRENTLY VERY LITTLE IS KNOWN ABOUT THE ORIGIN OF PROTEINS ON EARTH AND THEIR EVOLUTION IN EARLY MICROBIAL LIFE. TO FILL THIS KNOWLEDGE GAP THE ENIGMA RESEARCH PROGRAM WILL CARRY OUT EXPERIMENTAL BIOINFORMATIC DATA-DRIVEN ABDUCTIVE STUDIES TO EXPLORE THE ORIGIN OF CATALYSIS THE EVOLUTION OF PROTEIN STRUCTURES IN MICROBIAL ANCESTORS AND THE CO-EVOLUTION OF PROTEINS AND THE GEOSPHERE THROUGH GEOLOGIC TIME. ENIGMA HAS THREE INTEGRATED RESEARCH THEMES FOCUSED ON UNDERSTANDING THE EVOLUTION OF PROTEINS INVOLVED IN ELECTRON TRANSFER AND ENERGY GENERATION. THEME 1 WILL INVESTIGATE THE SYNTHESIS AND FUNCTION OF METALLOPROTEINS IN PREBIOTIC SYSTEMS. EXTANT MICROBIAL PROTEINS WILL BE ANALYZED TO IDENTIFY THE SIMPLEST STRUCTURES THAT CAN PERFORM ELECTRON TRANSFER REACTIONS. USING DE NOVO COMPUTATIONAL PROTEIN DESIGN SMALL PEPTIDES WILL BE SYNTHESIZED AND CHARACTERIZED TO ELUCIDATE THE EARLIEST BIOCHEMICAL REACTIONS IN THE ORIGIN OF LIFE. THEME 2 WILL EXAMINE THE EMERGENT COMPLEXITY OF METALLOPROTEINS IN MICROBIAL ANCESTORS. NEW COMPUTATIONAL METHODS LINKING PROTEIN STRUCTURE AND PHYLOGENY WILL BE DEVELOPED TO STUDY THE EVOLUTION OF METAL BINDING LIGANDS IN PROTEINS. A STRUCTURAL ALIGNMENT-BASED HOMOLOGY APPROACH WILL BE USED TO IDENTIFY THE OLDEST STRUCTURES IN PROTEINS AND TO TRACE THE EARLY EVOLUTION OF METAL BINDING FOLDS. THEME 3 WILL EXPLORE THE CO-EVOLUTION OF PROTEINS AND THE GEOSPHERE. DEEP-TIME DATA ON THE NATURE AND DISTRIBUTION OF REDOX-SENSITIVE ELEMENTS IN ROCKS AND MINERALS WILL BE INTEGRATED WITH PROTEIN STRUCTURAL DATA IN THE PROTEIN DATA BANK. MINERALOGICAL DATA (E.G. MINERAL COMPOSITION SOLUBILITY AND AGE) WILL BE INCORPORATED INTO GEOCHEMICAL MODELS TO CONSTRAIN THE BIOAVAILABILITY OF METALS OVER GEOLOGIC TIME AND METAL BIOAVAILABILITY DURING ARCHEAN AND PROTEROZOIC ERAS WILL USED TO DATE SPECIFIC POSITIONS IN THE EVOLUTIONARY TREE CONSTRUCTED IN THEME 2. THE THREE ENIGMA RESEARCH THEMES ARE DIRECTLY RELEVANT TO THE MAJOR TOPICS SYNTHESIS AND FUNCTION OF MACROMOLECULES IN THE ORIGIN OF LIFE EARLY LIFE AND INCREASING COMPLEXITY AND CO-EVOLUTION OF LIFE AND THE PHYSICAL ENVIRONMENT IDENTIFIED IN THE 2015 ASTROBIOLOGY SCIENCE STRATEGY. FURTHERMORE THE ENIGMA PROGRAM COMPLEMENTS THE NAI CAN 7 TEAMS ON EXPERIMENTAL MICROBIAL GENOMICS (GEORGIA TECH) AND LIFE ON A DYNAMIC EARLY EARTH (UC RIVERSIDE). THE RESULTS OF THE ENIGMA RESEARCH PROGRAM WILL HELP THE NAI ANSWER A CENTRAL QUESTION IN ASTROBIOLOGY: HOW DID PROTEINS EVOLVE TO BECOME THE CATALYSTS OF LIFE ON EARTH?, G8876996369
OpenAlex ID: W4385647882