Characterization of AMBN I and II Isoforms and Study of Their Ca2+-Binding Properties

Ameloblastin (Ambn) as an intrinsically disordered protein (IDP) stands for an important role in the formation of enamel—the hardest biomineralized tissue commonly formed in vertebrates. The human ameloblastin (AMBN) is expressed in two isoforms: full-length isoform I (AMBN ISO I) and isoform II (AMBN ISO II), which is about 15 amino acid residues shorter than AMBN ISO I. The significant feature of AMBN—its oligomerization ability—is enabled due to a specific sequence encoded by exon 5 present at the N-terminal part in both known isoforms. In this study, we characterized AMBN ISO I and AMBN ISO II by biochemical and biophysical methods to determine their common features and differences. We confirmed that both AMBN ISO I and AMBN ISO II form oligomers in in vitro conditions. Due to an important role of AMBN in biomineralization, we further addressed the calcium (Ca2+)-binding properties of AMBN ISO I and ISO II. The binding properties of AMBN to Ca2+ may explain the role of AMBN in biomineralization and more generally in Ca2+ homeostasis processes.

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Functional characterization of an unknown soybean intrinsically disordered protein in vitro and in Escherichia coli

International Journal of Biological Macromolecules ◽

10.1016/j.ijbiomac.2020.10.211 ◽

2021 ◽

Vol 166 ◽

pp. 538-549

Author(s):

Fangmei Tan ◽

Nan Sun ◽

Linsong Zhang ◽

Jiahui Wu ◽

Shifeng Xiao ◽

...

Keyword(s):

Escherichia Coli ◽

Functional Characterization ◽

Intrinsically Disordered Protein ◽

Intrinsically Disordered ◽

Disordered Protein

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Phospho-dependent phase separation of FMRP and CAPRIN1 recapitulates regulation of translation and deadenylation

Science ◽

10.1126/science.aax4240 ◽

2019 ◽

Vol 365 (6455) ◽

pp. 825-829 ◽

Cited By ~ 50

Author(s):

Tae Hun Kim ◽

Brian Tsang ◽

Robert M. Vernon ◽

Nahum Sonenberg ◽

Lewis E. Kay ◽

...

Keyword(s):

Phase Separation ◽

Rna Processing ◽

Intrinsically Disordered Protein ◽

Resonance Spectroscopy ◽

Specific Interactions ◽

Intrinsically Disordered ◽

Functional Consequences ◽

Translational Regulators

Membraneless organelles involved in RNA processing are biomolecular condensates assembled by phase separation. Despite the important role of intrinsically disordered protein regions (IDRs), the specific interactions underlying IDR phase separation and its functional consequences remain elusive. To address these questions, we used minimal condensates formed from the C-terminal disordered regions of two interacting translational regulators, FMRP and CAPRIN1. Nuclear magnetic resonance spectroscopy of FMRP-CAPRIN1 condensates revealed interactions involving arginine-rich and aromatic-rich regions. We found that different FMRP serine/threonine and CAPRIN1 tyrosine phosphorylation patterns control phase separation propensity with RNA, including subcompartmentalization, and tune deadenylation and translation rates in vitro. The resulting evidence for residue-specific interactions underlying co–phase separation, phosphorylation-modulated condensate architecture, and enzymatic activity within condensates has implications for how the integration of signaling pathways controls RNA processing and translation.

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NMR characterization of intramolecular interaction of osteopontin, an intrinsically disordered protein with cryptic integrin-binding motifs

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2010.02.030 ◽

2010 ◽

Vol 393 (3) ◽

pp. 487-491 ◽

Cited By ~ 10

Author(s):

Yoshiki Yamaguchi ◽

Shinya Hanashima ◽

Hirokazu Yagi ◽

Yutaka Takahashi ◽

Hiroaki Sasakawa ◽

...

Keyword(s):

Intramolecular Interaction ◽

Intrinsically Disordered Protein ◽

Binding Motifs ◽

Intrinsically Disordered ◽

Disordered Protein ◽

Nmr Characterization

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Synergism between a simple sugar and a small intrinsically disordered protein mitigate the lethal stresses of severe water loss

10.1101/209163 ◽

2017 ◽

Author(s):

Skylar X. Kim ◽

Gamze Çamdere ◽

Xuchen Hu ◽

Douglas Koshland ◽

Hugo Tapia

Keyword(s):

Water Loss ◽

Molecular Basis ◽

Intrinsically Disordered Protein ◽

Biological Functions ◽

Intrinsically Disordered ◽

Disordered Protein ◽

Drought Tolerant ◽

Simple Sugar

ABSTRACTAnhydrobiotes are rare microbes, plants and animals that tolerate severe water loss. Understanding the molecular basis for their desiccation tolerance may provide novel insights into stress biology and critical tools for engineering drought-tolerant crops. Using the anhydrobiote, budding yeast, we show that trehalose and Hsp12, a small intrinsically disordered protein (sIDP) of the hydrophilin family, synergize to mitigate completely the inviability caused by the lethal stresses of desiccation. We show that these two molecules help to stabilize the activity and prevent aggregation of model proteins both in vivo and in vitro. We also identify a novel role for Hsp12 as a membrane remodeler, a protective feature not shared by another yeast hydrophilin, suggesting that sIDPs have distinct biological functions.

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The Ambivalent Role of Proline Residues in an Intrinsically Disordered Protein: From Disorder Promoters to Compaction Facilitators

Journal of Molecular Biology ◽

10.1016/j.jmb.2019.11.015 ◽

2020 ◽

Vol 432 (9) ◽

pp. 3093-3111 ◽

Cited By ~ 12

Author(s):

Borja Mateos ◽

Clara Conrad-Billroth ◽

Marco Schiavina ◽

Andreas Beier ◽

Georg Kontaxis ◽

...

Keyword(s):

Intrinsically Disordered Protein ◽

Intrinsically Disordered ◽

Disordered Protein

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Interference with Amyloid-β Nucleation by Transient Ligand Interaction

Molecules ◽

10.3390/molecules24112129 ◽

2019 ◽

Vol 24 (11) ◽

pp. 2129 ◽

Cited By ~ 5

Author(s):

Tao Zhang ◽

Jennifer Loschwitz ◽

Birgit Strodel ◽

Luitgard Nagel-Steger ◽

Dieter Willbold

Keyword(s):

Amyloid Β ◽

Intrinsically Disordered Protein ◽

Amyloid Β Peptide ◽

Amino Acid Residues ◽

Ligand Interaction ◽

Drug Candidates ◽

Intrinsically Disordered ◽

Disordered Protein ◽

First Time ◽

Β Sheet

Amyloid-β peptide (Aβ) is an intrinsically disordered protein (IDP) associated with Alzheimer’s disease. The structural flexibility and aggregation propensity of Aβ pose major challenges for elucidating the interaction between Aβ monomers and ligands. All-D-peptides consisting solely of D-enantiomeric amino acid residues are interesting drug candidates that combine high binding specificity with high metabolic stability. Here we characterized the interaction between the 12-residue all-D-peptide D3 and Aβ42 monomers, and how the interaction influences Aβ42 aggregation. We demonstrate for the first time that D3 binds to Aβ42 monomers with submicromolar affinities. These two highly unstructured molecules are able to form complexes with 1:1 and other stoichiometries. Further, D3 at substoichiometric concentrations effectively slows down the β-sheet formation and Aβ42 fibrillation by modulating the nucleation process. The study provides new insights into the molecular mechanism of how D3 affects Aβ assemblies and contributes to our knowledge on the interaction between two IDPs.

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