scholarly journals Conformational propensities of intrinsically disordered proteins influence the mechanism of binding and folding

2015 ◽  
Vol 112 (31) ◽  
pp. 9614-9619 ◽  
Author(s):  
Munehito Arai ◽  
Kenji Sugase ◽  
H. Jane Dyson ◽  
Peter E. Wright
Keyword(s):  
Intrinsically Disordered Proteins ◽  
Terminal Region ◽  
Relaxation Dispersion ◽  
Disordered Proteins ◽  
Conformational Ensemble ◽  
Induced Fit ◽  
Conformational Selection ◽  
Intrinsically Disordered ◽  
Factor C ◽  
Binding Mechanisms

Intrinsically disordered proteins (IDPs) frequently function in protein interaction networks that regulate crucial cellular signaling pathways. Many IDPs undergo transitions from disordered conformational ensembles to folded structures upon binding to their cellular targets. Several possible binding mechanisms for coupled folding and binding have been identified: folding of the IDP after association with the target (“induced fit”), or binding of a prefolded state in the conformational ensemble of the IDP to the target protein (“conformational selection”), or some combination of these two extremes. The interaction of the intrinsically disordered phosphorylated kinase-inducible domain (pKID) of the cAMP-response element binding (CREB) protein with the KIX domain of a general transcriptional coactivator CREB-binding protein (CBP) provides an example of the induced-fit mechanism. Here we show by NMR relaxation dispersion experiments that a different intrinsically disordered ligand, the transactivation domain of the transcription factor c-Myb, interacts with KIX at the same site as pKID but via a different binding mechanism that involves elements of conformational selection and induced fit. In contrast to pKID, the c-Myb activation domain has a strong propensity for spontaneous helix formation in its N-terminal region, which binds to KIX in a predominantly folded conformation. The C-terminal region of c-Myb exhibits a much smaller helical propensity and likely folds via an induced-fit process after binding to KIX. We propose that the intrinsic secondary structure propensities of pKID and c-Myb determine their binding mechanisms, consistent with their functions as inducible and constitutive transcriptional activators.

scholarly journals Reinforcement Learning to Boost Molecular Docking upon Protein Conformational Ensemble

2021 ◽  
Author(s):  
Bin Chong ◽  
Yingguang Yang ◽  
Zi-Le Wang ◽  
Han Xing ◽  
Zhirong Liu
Keyword(s):  
Molecular Docking ◽  
Reinforcement Learning ◽  
Intrinsically Disordered Proteins ◽  
Therapeutic Targets ◽  
Human Diseases ◽  
Disordered Proteins ◽  
Conformational Ensemble ◽  
Intrinsically Disordered

Intrinsically disordered proteins (IDPs) widely involve in human diseases and are thus attractive therapeutic targets. In practice, however, it is computationally prohibitive to dock large ligand libraries to thousands and...

scholarly journals A comprehensive motifs-based interactome of the C/EBPα transcription factor

2020 ◽  
Author(s):  
Evelyn Ramberger ◽  
Valeria Sapozhnikova ◽  
Elisabeth Kowenz-Leutz ◽  
Karin Zimmermann ◽  
Nathalie Nicot ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Protein Interaction ◽  
Intrinsically Disordered Proteins ◽  
Arginine Methylation ◽  
Disordered Proteins ◽  
List Type ◽  
Short Linear Motifs ◽  
Intrinsically Disordered ◽  
Linear Motifs ◽  
Factor C

AbstractThe pioneering transcription factor C/EBPα coordinates cell fate and cell differentiation. C/EBPα represents an intrinsically disordered protein with multiple short linear motifs and extensive post-translational side chain modifications (PTM), reflecting its modularity and functional plasticity. Here, we combined arrayed peptide matrix screening (PRISMA) with biotin ligase proximity labeling proteomics (BioID) to generate a linear, isoform specific and PTM-dependent protein interaction map of C/EBPα in myeloid cells. The C/EBPα interactome comprises promiscuous and PTM-regulated interactions with protein machineries involved in gene expression, epigenetics, genome organization, DNA replication, RNA processing, and nuclear transport as the basis of functional C/EBPα plasticity. Protein interaction hotspots were identified that coincide with homologous conserved regions of the C/EBP family and revealed interaction motifs that score as molecular recognition features (MoRF). PTMs alter the interaction spectrum of multi-valent C/EBP-motifs to configure a multimodal transcription factor hub that allows interaction with multiple co-regulatory components, including BAF/SWI-SNF or Mediator complexes. Combining PRISMA and BioID acts as a powerful strategy to systematically explore the interactomes of intrinsically disordered proteins and their PTM-regulated, multimodal capacity.Key pointsIntegration of proximity labeling and arrayed peptide screen proteomics refines the interactome of C/EBPα isoformsHotspots of protein interactions in C/EBPα mostly occur in conserved short linear motifsInteractions of the BAF/SWI-SNF complex with C/EBPα are modulated by arginine methylation and isoform statusThe integrated experimental strategy suits systematic interactome studies of intrinsically disordered proteins

scholarly journals Targeting Intrinsically Disordered Proteins through Dynamic Interactions

Biomolecules ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 743
Author(s):  
Jianlin Chen ◽  
Xiaorong Liu ◽  
Jianhan Chen
Keyword(s):  
Small Molecules ◽  
Intrinsically Disordered Proteins ◽  
Gpu Computing ◽  
Disordered Proteins ◽  
Atomistic Simulations ◽  
Conformational Ensemble ◽  
Processing Unit ◽  
Dynamic Interactions ◽  
Intrinsically Disordered ◽  
Interaction Sites

Intrinsically disordered proteins (IDPs) are over-represented in major disease pathways and have attracted significant interest in understanding if and how they may be targeted using small molecules for therapeutic purposes. While most existing studies have focused on extending the traditional structure-centric drug design strategies and emphasized exploring pre-existing structure features of IDPs for specific binding, several examples have also emerged to suggest that small molecules could achieve specificity in binding IDPs and affect their function through dynamic and transient interactions. These dynamic interactions can modulate the disordered conformational ensemble and often lead to modest compaction to shield functionally important interaction sites. Much work remains to be done on further elucidation of the molecular basis of the dynamic small molecule–IDP interaction and determining how it can be exploited for targeting IDPs in practice. These efforts will rely critically on an integrated experimental and computational framework for disordered protein ensemble characterization. In particular, exciting advances have been made in recent years in enhanced sampling techniques, Graphic Processing Unit (GPU)-computing, and protein force field optimization, which have now allowed rigorous physics-based atomistic simulations to generate reliable structure ensembles for nontrivial IDPs of modest sizes. Such de novo atomistic simulations will play crucial roles in exploring the exciting opportunity of targeting IDPs through dynamic interactions.

scholarly journals Molecular Dynamics Simulations of Phosphorylated Intrinsically Disordered Proteins: A Force Field Comparison

2021 ◽  
Vol 22 (18) ◽  
pp. 10174
Author(s):  
Ellen Rieloff ◽  
Marie Skepö
Keyword(s):  
Force Field ◽  
Intrinsically Disordered Proteins ◽  
Disordered Proteins ◽  
Conformational Ensemble ◽  
Salt Bridges ◽  
Post Translational Modification ◽  
Intrinsically Disordered ◽  
The Difference ◽  
Disordered Peptides ◽  
Dynamics Simulations

Phosphorylation is a common post-translational modification among intrinsically disordered proteins and regions, which helps regulate function by changing the protein conformations, dynamics, and interactions with binding partners. To fully comprehend the effects of phosphorylation, computer simulations are a helpful tool, although they are dependent on the accuracy of the force field used. Here, we compared the conformational ensembles produced by Amber ff99SB-ILDN+TIP4P-D and CHARMM36m, for four phosphorylated disordered peptides ranging in length from 14–43 residues. CHARMM36m consistently produced more compact conformations with a higher content of bends, mainly due to more stable salt bridges. Based on comparisons with experimental size estimates for the shortest and longest peptide, CHARMM36m appeared to overestimate the compactness. The difference between the force fields was largest for the peptide showing the greatest separation between positively charged and phosphorylated residues, in line with the importance of charge distribution. For this peptide, the conformational ensemble did not change significantly upon increasing the ionic strength from 0 mM to 150 mM, despite a reduction of the salt-bridging probability in the CHARMM36m simulations, implying that salt concentration has negligible effects in this study.

scholarly journals Exploring Energy Landscapes of Intrinsically Disordered Proteins: Insights into Functional Mechanisms

2021 ◽  
Author(s):  
Antonio B. Oliveira ◽  
Xingcheng Lin ◽  
Prakash Kulkarni ◽  
José N. Onuchic ◽  
Susmita Roy ◽  
...  
Keyword(s):  
Intrinsically Disordered Proteins ◽  
Energy Landscape ◽  
3D Structure ◽  
Intrinsically Disordered Protein ◽  
Terminal Segment ◽  
Disordered Proteins ◽  
Conformational Ensemble ◽  
Energy Landscapes ◽  
Reaction Coordinates ◽  
Intrinsically Disordered

AbstractIntrinsically disordered proteins (IDPs) lack a rigid 3D structure and populate a polymorphic ensemble of conformations. Because of the lack of a reference conformation, their energy landscape representation in terms of reaction coordinates presents a daunting challenge. Here, our newly developed Energy Landscape Visualization Method (ELViM), a reaction coordinate-free approach, shows its prime application to explore frustrated energy landscapes of an intrinsically disordered protein, Prostate-Associated Gene 4 (PAGE4). PAGE4 is a transcriptional coactivator that potentiates the oncogene c-Jun. Two kinases, namely HIPK1 and CLK2, phosphorylate PAGE4 generating variants phosphorylated at different serine/threonine residues (HIPK1-PAGE4 and CLK2-PAGE4, respectively) with opposing functions. While HIPK1-PAGE4 predominantly phosphorylates Thr51 and potentiates c-Jun, CLK2-PAGE4 hyper-phosphorylates PAGE4 and attenuates transactivation. To understand the underlying mechanisms of conformational diversity among different phosphoforms, we have analyzed their atomistic trajectories simulated using AWSEM forcefield and the energy landscapes were elucidated using ELViM. This method allows us to identify and compare the population distributions of different conformational ensembles of PAGE4 phosphoforms using the same effective phase space. The results reveal a predominant conformational ensemble with an extended C-terminal segment of WT PAGE4, which exposes a functional residue Thr51, implying its potential of undertaking a fly-casting mechanism while binding to its cognate partner. In contrast, for HIPK1-PAGE4, a compact conformational ensemble enhances its population sequestering phosphorylated-Thr51. This clearly explains the experimentally observed weaker affinity of HIPK1-PAGE4 for c-Jun. ELViM appears as a powerful tool especially to analyze the highly-frustrated energy landscape representation of IDPs where appropriate reaction coordinates are hard to apprehend.

scholarly journals Multisite Phosphorylation and Binding Alter Conformational Dynamics of the 4E-BP2 Protein

2022 ◽  
Author(s):  
Spencer Smyth ◽  
Zhenfu Zhang ◽  
Alaji Bah ◽  
Thomas Tsangaris ◽  
Jennifer Dawson ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Intrinsically Disordered Proteins ◽  
Regulatory Protein ◽  
Conformational Dynamics ◽  
Correlation Spectroscopy ◽  
Terminal Region ◽  
Disordered Proteins ◽  
Initiation Factor ◽  
Dependent Manner ◽  
Intrinsically Disordered

Intrinsically disordered proteins (IDPs) play critical roles in regulatory protein interactions, but detailed structural/dynamics characterization of their ensembles remain challenging, both in isolation and they form dynamic fuzzy complexes. Such is the case for mRNA cap-dependent translation initiation, which is regulated by the interaction of the predominantly folded eukaryotic initiation factor 4E (eIF4E) with the intrinsically disordered eIF4E binding proteins (4E-BPs) in a phosphorylation-dependent manner. Single-molecule Forster resonance energy transfer showed that the conformational changes of 4E-BP2 induced by binding to eIF4E are non-uniform along the sequence; while a central region containing both motifs that bind to eIF4E expands and becomes stiffer, the C-terminal region is less affected. Fluorescence anisotropy decay revealed a nonuniform segmental flexibility around six different labelling sites along the chain. Dynamic quenching of these fluorescent probes by intrinsic aromatic residues measured via fluorescence correlation spectroscopy report on transient intra- and inter-molecular contacts on nanosecond-microsecond timescales. Upon hyperphosphorylation, which induces folding of ~40 residues in 4E-BP2, the quenching rates decreased at labelling sites closest to the phosphorylation sites and within the folded domain, and increased at the other sites. The chain dynamics around sites in the C-terminal region far away from the two binding motifs were significantly reduced upon binding to eIF4E, suggesting that this region is also involved in the highly dynamic 4E-BP2:eIF4E complex. Our time-resolved fluorescence data paint a sequence-level rigidity map of three states of 4E-BP2 differing in phosphorylation or binding status and distinguish regions that form contacts with eIF4E. This study adds complementary structural and dynamics information to recent studies of 4E-BP2, and it constitutes an important step towards a mechanistic understanding of this important IDP via integrative modelling.

scholarly journals Characterization of Weak Protein Domain Structure by Spin-Label Distance Distributions

2021 ◽  
Vol 8 ◽  
Author(s):  
Irina Ritsch ◽  
Laura Esteban-Hofer ◽  
Elisabeth Lehmann ◽  
Leonidas Emmanouilidis ◽  
Maxim Yulikov ◽  
...  
Keyword(s):  
Intrinsically Disordered Proteins ◽  
Distance Distribution ◽  
Protein Domain ◽  
Random Coil ◽  
Disordered Proteins ◽  
Primary Data ◽  
Spin Labels ◽  
Conformational Ensemble ◽  
Intrinsically Disordered ◽  
Distance Distributions

Function of intrinsically disordered proteins may depend on deviation of their conformational ensemble from that of a random coil. Such deviation may be hard to characterize and quantify, if it is weak. We explored the potential of distance distributions between spin labels, as they can be measured by electron paramagnetic resonance techniques, for aiding such characterization. On the example of the intrinsically disordered N-terminal domain 1–267 of fused in sarcoma (FUS) we examined what such distance distributions can and cannot reveal on the random-coil reference state. On the example of the glycine-rich domain 188–320 of heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) we studied whether deviation from a random-coil ensemble can be robustly detected with 19 distance distribution restraints. We discuss limitations imposed by ill-posedness of the conversion of primary data to distance distributions and propose overlap of distance distributions as a fit criterion that can tackle this problem. For testing consistency and size sufficiency of the restraint set, we propose jack-knife resampling. At current desktop computers, our approach is expected to be viable for domains up to 150 residues and for between 10 and 50 distance distribution restraints.

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