Folding mechanisms steer the amyloid fibril formation propensity of highly homologous proteins

Malgieri, Gaetano; D’Abrosca, Gianluca; Pirone, Luciano; Toto, Angelo; Palmieri, Maddalena; Russo, Luigi; Sciacca, Michele F.M.; Tatè, Rosarita; Sivo, Valeria; Baglivo, Ilaria; Majewska, Roksana; Coletta, Massimo; Pedone, Paolo V.; Isernia, Carla; Stefano, Mario De; Gianni, Stefano; Pedone, Emilia; Milardi, Danilo; Fattorusso, Roberto

doi:10.1039/c8sc00166a

Cited by 17 publications

(19 citation statements)

References 43 publications

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“…In all the EMSAs carried out with 20 bp oligonucleotides, the highest amount of protein used does not result in more bound DNA. This is in agreement with what we observed with the other proteins of the Ros/MucR family and it is likely due to the aggregation propensity of these proteins being able to form higher-order oligomers [12,37].…”

Section: Mucr Binds the Promoters Of Babr And Virb Genessupporting

confidence: 92%

Different Impacts of MucR Binding to the babR and virB Promoters on Gene Expression in Brucella abortus 2308

Borriello¹,

Russo

Paradiso³

et al. 2020

Biomolecules

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The protein MucR from Brucella abortus has been described as a transcriptional regulator of many virulence genes. It is a member of the Ros/MucR family comprising proteins that control the expression of genes important for the successful interaction of α-proteobacteria with their eukaryotic hosts. Despite clear evidence of the role of MucR in repressing virulence genes, no study has been carried out so far demonstrating the direct interaction of this protein with the promoter of its target gene babR encoding a LuxR-like regulator repressing virB genes. In this study, we show for the first time the ability of MucR to bind the promoter of babR in electrophoretic mobility shift assays demonstrating a direct role of MucR in repressing this gene. Furthermore, we demonstrate that MucR can bind the virB gene promoter. Analyses by RT-qPCR showed no significant differences in the expression level of virB genes in Brucella abortus CC092 lacking MucR compared to the wild-type Brucella abortus strain, indicating that MucR binding to the virB promoter has little impact on virB gene expression in B. abortus 2308. The MucR modality to bind the two promoters analyzed supports our previous hypothesis that this is a histone-like protein never found before in Brucella.

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Section: Mucr Binds the Promoters Of Babr And Virb Genessupporting

confidence: 92%

Different Impacts of MucR Binding to the babR and virB Promoters on Gene Expression in Brucella abortus 2308

Borriello¹,

Russo

Paradiso³

et al. 2020

Biomolecules

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“…The samples were excited at a wavelength of 440 nm and the fluorescence emission spectrum was recorded between 450 and 600 nm. The samples were incubated at 37 °C and the fluorescence intensity change was monitored at 485 nm over time .…”

Section: Methodsmentioning

confidence: 99%

Molecular insights into the role of the polyalanine region in mediating PHOX2B aggregation

et al. 2019

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About 90% of congenital central hypoventilation syndrome (CCHS) patients show polyalanine triplet expansions in the coding region of transcription factor PHOX2B, which renders this protein an intriguing target to understand the insurgence of this syndrome and for the design of a novel therapeutical approach. Consistently with the role of PHOX2B as a transcriptional regulator, it is reasonable that a general transcriptional dysregulation caused by the polyalanine expansion might represent an important mechanism underlying CCHS pathogenesis. Therefore, this study focused on the biochemical characterization of different PHOX2B variants, such as a variant containing the correct C‐terminal (20 alanines) stretch, one of the most frequent polyalanine expansions (+7 alanines), and a variant lacking the complete alanine stretch (0 alanines). Comparison of the different variants by a multidisciplinary approach based on different methodologies (including circular dichroism, spectrofluorimetry, light scattering, and Atomic Force Microscopy studies) highlighted the propensity to aggregate for the PHOX2B variant containing the polyalanine expansion (+7‐alanines), especially in the presence of DNA, while the 0‐alanines variant resembled the protein with the correct polyalanine length. Moreover, and unexpectedly, the formation of fibrils was revealed only for the pathological variant, suggesting a plausible role of such fibrils in the insurgence of CCHS.

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“…The thermal stability of peptide's secondary structures was investigated by a temperature-induced folding-unfolding study. [26] For this, CD experiments were performed for AV20 and G37 L at different temperatures ( Figure 4A, B). AV20 showed a minimal effect on the secondary conformation.…”

Section: Thermal Stability and Solvent Dynamics Plays A Crucial Role mentioning

confidence: 99%

Self‐Assembly and Neurotoxicity of β‐Amyloid (21–40) Peptide Fragment: The Regulatory Role of GxxxG Motifs

et al. 2019

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The three GxxxG repeating motifs from the C-terminal region of β-amyloid (Aβ) peptide play a significant role in regulating the aggregation kinetics of the peptide. Mutation of these glycine residues to leucine greatly accelerates the fibrillation process but generates a varied toxicity profile. Using an array of biophysical techniques, we demonstrated the uniqueness of the composite glycine residues in these structural repeats. We used solvent relaxation NMR spectroscopy to investigate the role played by the surrounding water molecules in determining the corresponding aggregation pathway. Notably, the conformational changes induced by Gly 33 and Gly 37 mutations result in significantly decreased toxicity in a neuronal cell line. Our results indicate that G 33 xxxG 37 is the primary motif responsible for Aβ neurotoxicity, hence providing a direct structurefunction correlation. Targeting this motif, therefore, can be a promising strategy to prevent neuronal cell death associated with Alzheimer's and other related diseases, such as type II diabetes and Parkinson's. ROESY were 48 and 64, respectively. Data processing and analysis were carried out using Topspin TM v3.2 software (Bruker Biospin, Switzerland) and Sparky (https://www.cgl.ucsf.edu/home/sparky) software, respectively.

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Folding mechanisms steer the amyloid fibril formation propensity of highly homologous proteins

Abstract: Understanding the molecular determinants of fibrillogenesis by studying the aggregation propensities of high homologous proteins with different folding pathways.

Cited by 17 publications

References 43 publications

Different Impacts of MucR Binding to the babR and virB Promoters on Gene Expression in Brucella abortus 2308

Different Impacts of MucR Binding to the babR and virB Promoters on Gene Expression in Brucella abortus 2308

Molecular insights into the role of the polyalanine region in mediating PHOX2B aggregation

Self‐Assembly and Neurotoxicity of β‐Amyloid (21–40) Peptide Fragment: The Regulatory Role of GxxxG Motifs

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