title: A polymorphic position in electron transfer flavoprotein modulates kinetic stability as evidenced by thermal stress.
abstract: The electron transfer flavoprotein (ETF) is a hub interacting with at least 11 mitochondrial flavoenzymes and linking them to the respiratory chain. Here we report the effect of the ETFα-T/I171 polymorphism on protein conformation and kinetic stability under thermal stress. Although variants have comparable thermodynamic stabilities, kinetically their behavior is rather distinct as ETFα-T171 displays increased susceptibility to cofactor flavin adenine dinucleotide (FAD) loss and enhanced kinetics of inactivation during thermal stress. Mimicking a fever episode yields substantial activity loss. However, the presence of substoichiometric concentrations of GroEL is sufficient to act as an effective buffer against long-term thermal denaturation. Our investigations are compatible with the notion that the ETFα-T171 variant displays an altered conformational landscape that results in reduced protein function under thermal stress.
authors.affiliation: Instituto Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: Bárbara J
authors.initials: BJ
authors.lastname: Henriques
authors.forename: Mark T
authors.initials: MT
authors.lastname: Fisher
authors.forename: Peter
authors.initials: P
authors.lastname: Bross
authors.forename: Cláudio M
authors.initials: CM
authors.lastname: Gomes
mesh_terms: D019943:Amino Acid Substitution; D018834:Chaperonin 60 / Q000737:chemistry / Q000378:metabolism; D002942:Circular Dichroism; D044927:Electron-Transferring Flavoproteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism; D005334:Fever / Q000378:metabolism; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D056726:Genetic Association Studies; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D007700:Kinetics; D011110:Polymorphism, Genetic; D011487:Protein Conformation; D011489:Protein Denaturation; D055550:Protein Stability; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry
chemical_list: D018834:Chaperonin 60; C500318:ETFA protein, human; D044927:Electron-Transferring Flavoproteins; D029968:Escherichia coli Proteins; D011994:Recombinant Proteins; D005182:Flavin-Adenine Dinucleotide