Naturally Occurring A51V Variant of Human Cytochrome <i>c</i> Destabilizes the Native State and Enhances Peroxidase Activity

Lei, Haotian; Bowler, Bruce E.

doi:10.1021/acs.jpcb.9b05869

Cited by 28 publications

(29 citation statements)

References 94 publications

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“…No differences in the far-UV CD profiles for the WT or any of the variants in a temperature range between 10 and 30 o C were observed (data not shown). The X-ray structures of the three variants, [5,42,48], reveal no significant secondary structure differences in respect to the WT structure. [23] In contrast, solution NMR studies indicate that the G41S and Y48H variants are more dynamic than the WT protein.…”

Section: Far-uv CD Spectroscopy Of the Ferric A51v Variant And Comparmentioning

confidence: 87%

Comparison of the structural dynamic and mitochondrial electron-transfer properties of the proapoptotic human cytochrome c variants, G41S, Y48H and A51V

Deacon

White

Moore

et al. 2020

Journal of Inorganic Biochemistry

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Mitochondrial cytochrome c is associated with electron transfer in the respiratory chain and in apoptosis. Four cytochrome c variants have been identified in families that suffer from mild autosomal dominant thrombocytopenia, a platelet disorder associated with increased apoptosis. Three out of the four substitutions, G41S, Y48H and A51V are located on the 40-57 Ω-loop. The G41S and Y48H variants perturb key physicochemical and dynamic properties that result in enhanced functional features associated with apoptotic activity. Herein we characterise the ferric A51V variant. We show by chemical denaturation that this variant causes the native state to be destabilized. Through azide binding kinetics, the population of a pentacoordinate heme form, whereby the Met80 axial ligand is dissociated, is estimated to be of equal magnitude to that found in the Y48H variant. This pentacoordinate form gives rise to peroxidase activity, which despite the similar pentacoordinate population of the A51V variant to that of the Y48H variant, the peroxidase activity of the A51V variant is supressed. Far-UV circular dichroism spectroscopy and pH jump studies, suggest that a combination of structural and dynamic features in addition to the population of the pentacoordinate form regulate peroxidase activity in these disease variants. Additionally, the steady-state ratio of ferric/ferrous cytochrome c when in turnover with cytochrome c oxidase has been investigated for all 40-57 Ω-loop variants. These studies show that the lower pKa of the alkaline transition for the disease causing variants increases the ferric to ferrous heme ratio, indicating a possible influence on respiration in vivo.

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Section: Far-uv CD Spectroscopy Of the Ferric A51v Variant And Comparmentioning

confidence: 87%

Comparison of the structural dynamic and mitochondrial electron-transfer properties of the proapoptotic human cytochrome c variants, G41S, Y48H and A51V

Deacon

White

Moore

et al. 2020

Journal of Inorganic Biochemistry

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“…As noted above, the ssNMR data identify increased mobility not only in membrane-facing regions, but also in other segments such as loop C. Thus, it is possible that loop C dynamics play a role in the activation of cyt c’s peroxidase function. This kind of role is supported by recent studies of cyt c mutants showing that mutations in loop C can also regulate cyt c peroxidase activity [90–92]. Lei et al determined the X-ray crystal structure of the A51V variant of cyt c, which shows only minor changes in tertiary structure compared to the WT protein, but exhibits several folds of increase in peroxidase activity [90].…”

Section: Discussionmentioning

confidence: 92%

“…This kind of role is supported by recent studies of cyt c mutants showing that mutations in loop C can also regulate cyt c peroxidase activity [75][76][77]. Lei et al determined the structure of a A51V variant of cyt c, which shows only minor changes in tertiary structure compared to the WT protein, however, exhibits several folds of increase in peroxidase activity [75]. A G41T mutation causes increased mobility of both loops C and D, resulting in loop D destabilization [77].…”

Section: On Lipid-induced Allosteric Mobility Affecting Cyt C Loop Cmentioning

confidence: 90%

Activation of Cytochrome C Peroxidase Function Through Coordinated Foldon Loop Dynamics upon Interaction with Anionic Lipids

Sun

Tyurin

et al. 2021

Preprint

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Cardiolipin (CL) is a mitochondrial anionic lipid that plays important roles in the regulation and signaling of mitochondrial apoptosis. CL peroxidation catalyzed by the assembly of CL-cytochrome c (cyt c) complexes at the inner mitochondrial membrane is a critical checkpoint. The structural changes in the protein, associated with peroxidase activation by CL and different anionic lipids, are not known at a molecular level. To better understand these peripheral protein-lipid interactions, we compare how phosphatidylglycerol (PG) and CL lipids trigger cyt c peroxidase activation, and correlate functional differences to structural and motional changes in membrane-associated cyt c. Structural and motional studies of the bound protein are enabled by magic angle spinning solid state NMR spectroscopy, while lipid peroxidase activity is assayed by mass spectrometry. PG binding results in a surface-bound state that preserves a nativelike fold, which nonetheless allows for significant peroxidase activity, though at a lower level than binding its native substrate CL. Lipid-specific differences in peroxidase activation are found to correlate to corresponding differences in lipid-induced protein mobility, affecting specific protein segments. The dynamics of omega loops C and D are upregulated by CL binding, in a way that is remarkably controlled by the protein:lipid stoichiometry. In contrast to complete chemical denaturation, membrane-induced protein destabilization reflects a destabilization of select cyt c foldons, while the energetically most stable helices are preserved. Our studies illuminate the interplay of protein and lipid dynamics in the creation of lipid peroxidase-active proteolipid complexes implicated in early stages of mitochondrial apoptosis.

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“…De Rocco et al reported that the p. Gly42Ser and p.Tyr49His variants in yeast and mouse cellular models were responsible of the diminished respiratory level and increased apoptotic rate ( De Rocco et al, 2014 ). Lei et al showed that the Ala51Val variant enhanced peroxidase activity by destabilizing the native state of Cyt-c, and all three variants Gly42Ser, Tyr49His, and Ala51Val had reduced global and local stability than that of wild type Cyt-c ( Lei and Bowler, 2019 ). Moreover, Uchiyama et al provided that the mutation of p.Lys301del could significantly reduced cytochrome c protein expression and cause functional defects in the mitochondrial respiratory chain ( Uchiyama et al, 2018 ).…”

Section: Discussionmentioning

confidence: 99%

A Novel Heterozygous Pathogenic Variation in CYCS Gene Cause Autosomal Dominant Non-Syndromic Thrombocytopenia 4 in a Large Chinese Family

Che

Zhao

et al. 2022

Front. Genet.

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Aim: To determine the etiology of a Chinese family with thrombocytopenia by analyzing the clinical features and genetic variation.Methods: Clinical profiles and genomic DNA extracts of the family members were collected for the study. Whole exome sequencing and Sanger sequencing was used to detect the associated genetic variation and verify the family co-segregation respectively. Bioinformatics analysis assessed the pathogenicity of missense mutations.Results: The study reported a 3-generation pedigree including eight family members with thrombocytopenia. The platelet counts of the patients were varied, ranging from 38 to 110 × 109/L (reference range: 150–450 x 109/L). The mean volumes and morphology of the sampled platelet were both normal. The bleeding abnormality and mitochondriopathy were not observed in all the patients. Clinical signs of thrombocytopenia were mild. A novel heterozygous missense variant c.79C > T (p.His27Tyr) was identified in CYCS gene associated with autosomal dominant thrombocytopenia.Conclusion: We report the first large family with autosomal dominant non-syndromic thrombocytopenia 4 in a Chinese family, a novel heterozygous missense variant c.79C > T (p.His27Tyr) was identified. The whole exome sequencing is an efficient tool for screening the variants specifically associated with the disease. The finding enriches the mutation spectrum of CYCS gene and laid a foundation for future studies on the correlation between genotype and phenotype.

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Naturally Occurring A51V Variant of Human Cytochrome c Destabilizes the Native State and Enhances Peroxidase Activity

Cited by 28 publications

References 94 publications

Comparison of the structural dynamic and mitochondrial electron-transfer properties of the proapoptotic human cytochrome c variants, G41S, Y48H and A51V

Comparison of the structural dynamic and mitochondrial electron-transfer properties of the proapoptotic human cytochrome c variants, G41S, Y48H and A51V

Activation of Cytochrome C Peroxidase Function Through Coordinated Foldon Loop Dynamics upon Interaction with Anionic Lipids

A Novel Heterozygous Pathogenic Variation in CYCS Gene Cause Autosomal Dominant Non-Syndromic Thrombocytopenia 4 in a Large Chinese Family

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