scholarly journals Atomistic Structure and Dynamics of the Ca2+-ATPase Bound to Phosphorylated Phospholamban

2020 ◽  
Vol 21 (19) ◽  
pp. 7261
Author(s):  
Rodrigo Aguayo-Ortiz ◽  
L. Michel Espinoza-Fonseca
Keyword(s):  
Water Environment ◽  
Stable Complex ◽  
Atomistic Model ◽  
Structural Mechanism ◽  
Essential Components ◽  
Transmembrane Regions ◽  
Dynamics Simulations ◽  
Atomistic Structure ◽  
Phosphorylation Domain ◽  
Serca Inhibition

Sarcoplasmic reticulum Ca2+-ATPase (SERCA) and phospholamban (PLB) are essential components of the cardiac Ca2+ transport machinery. PLB phosphorylation at residue Ser16 (pSer16) enhances SERCA activity in the heart via an unknown structural mechanism. Here, we report a fully atomistic model of SERCA bound to phosphorylated PLB and study its structural dynamics on the microsecond time scale using all-atom molecular dynamics simulations in an explicit lipid bilayer and water environment. The unstructured N-terminal phosphorylation domain of PLB samples different orientations and covers a broad area of the cytosolic domain of SERCA but forms a stable complex mediated by pSer16 interactions with a binding site formed by SERCA residues Arg324/Lys328. PLB phosphorylation does not affect the interaction between the transmembrane regions of the two proteins; however, pSer16 stabilizes a disordered structure of the N-terminal phosphorylation domain that releases key inhibitory contacts between SERCA and PLB. We found that PLB phosphorylation is sufficient to guide the structural transitions of the cytosolic headpiece that are required to produce a competent structure of SERCA. We conclude that PLB phosphorylation serves as an allosteric molecular switch that releases inhibitory contacts and strings together the catalytic elements required for SERCA activation. This atomistic model represents a vivid atomic-resolution visualization of SERCA bound to phosphorylated PLB and provides previously inaccessible insights into the structural mechanism by which PLB phosphorylation releases SERCA inhibition in the heart.

scholarly journals Structural basis for relief of the sarcoplasmic reticulum Ca2+-ATPase inhibition by phospholamban at saturating Ca2+ conditions

2018 ◽  
Author(s):  
Eli Fernández-de Gortari ◽  
L. Michel Espinoza-Fonseca
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Structural Features ◽  
Structural Basis ◽  
Initial Structure ◽  
Structural Mechanism ◽  
Cytosolic Side ◽  
Dynamics Simulations ◽  
Atpase Inhibition ◽  
Inhibitory Interactions ◽  
Serca Inhibition

AbstractWe have performed extensive atomistic molecular dynamics simulations to probe the structural mechanism for relief of sarcoplasmic reticulum Ca2+-ATPase (SERCA) inhibition by phospholamban (PLB) at saturating Ca2+ conditions. Reversal of SERCA-PLB inhibition by saturating Ca2+ operates as a physiological rheostat to reactivate SERCA function in the absence of PLB phosphorylation. Simulation of the inhibitory complex at super-physiological Ca2+ concentrations ([Ca2+]=10 mM) revealed that calcium ions interact primarily with SERCA and the lipid headgroups, but not with the cytosolic domain of PLB or the cytosolic side of the SERCA-PLB interface. At this [Ca2+], a single Ca2+ ion is translocated from the cytosol to the transmembrane transport sites. We used this Ca2+-bound complex as an initial structure to simulate the effects of saturating Ca2+ at physiological conditions ([Ca2+]total≈400 μM). At these conditions, ~30% of the Ca2+-bound complexes exhibit structural features that correspond to an inhibited state. However, in ~70% of the Ca2+-bound complexes, Ca2+ moves to transport site I, recruits Glu771 and Asp800, and disrupts key inhibitory contacts involving conserved PLB residue Asn34. Structural analysis showed that Ca2+ induces only local changes in interresidue inhibitory interactions, but does not induce dissociation, repositioning or changes in the structural dynamics of PLB. Upon relief of SERCA inhibition, Ca2+ binding produces a productive site I configuration that is sufficient for subsequent SERCA activation. We propose that at saturating [Ca2+] and in the absence of PLB phosphorylation, binding of a single Ca2+ ion in the transport sites rapidly shifts the equilibrium toward a non-inhibited SERCA-PLB complex.

scholarly journals Kinetic and structural mechanism for DNA unwinding by a non-hexameric helicase

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sean P. Carney ◽  
Wen Ma ◽  
Kevin D. Whitley ◽  
Haifeng Jia ◽  
Timothy M. Lohman ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Single Molecule ◽  
Atp Hydrolysis ◽  
Variable Number ◽  
Structural Basis ◽  
Variable Step Size ◽  
Dna Unwinding ◽  
Step Size ◽  
Structural Mechanism ◽  
Dynamics Simulations

AbstractUvrD, a model for non-hexameric Superfamily 1 helicases, utilizes ATP hydrolysis to translocate stepwise along single-stranded DNA and unwind the duplex. Previous estimates of its step size have been indirect, and a consensus on its stepping mechanism is lacking. To dissect the mechanism underlying DNA unwinding, we use optical tweezers to measure directly the stepping behavior of UvrD as it processes a DNA hairpin and show that UvrD exhibits a variable step size averaging ~3 base pairs. Analyzing stepping kinetics across ATP reveals the type and number of catalytic events that occur with different step sizes. These single-molecule data reveal a mechanism in which UvrD moves one base pair at a time but sequesters the nascent single strands, releasing them non-uniformly after a variable number of catalytic cycles. Molecular dynamics simulations point to a structural basis for this behavior, identifying the protein-DNA interactions responsible for strand sequestration. Based on structural and sequence alignment data, we propose that this stepping mechanism may be conserved among other non-hexameric helicases.

scholarly journals Exploring Aurone Derivatives as Potential Human Pancreatic Lipase Inhibitors through Molecular Docking and Molecular Dynamics Simulations

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4657
Author(s):  
Phuong Thuy Viet Nguyen ◽  
Han Ai Huynh ◽  
Dat Van Truong ◽  
Thanh-Dao Tran ◽  
Cam-Van Thi Vo
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Pancreatic Lipase ◽  
Inhibitory Activity ◽  
Dynamics Simulation ◽  
Stable Complex ◽  
Catalytic Active Site ◽  
Dynamics Simulations

Inhibition of human pancreatic lipase, a crucial enzyme in dietary fat digestion and absorption, is a potent therapeutic approach for obesity treatment. In this study, human pancreatic lipase inhibitory activity of aurone derivatives was explored by molecular modeling approaches. The target protein was human pancreatic lipase (PDB ID: 1LPB). The 3D structures of 82 published bioactive aurone derivatives were docked successfully into the protein catalytic active site, using AutoDock Vina 1.5.7.rc1. Of them, 62 compounds interacted with the key residues of catalytic trial Ser152-Asp176-His263. The top hit compound (A14), with a docking score of −10.6 kcal⋅mol−1, was subsequently submitted to molecular dynamics simulations, using GROMACS 2018.01. Molecular dynamics simulation results showed that A14 formed a stable complex with 1LPB protein via hydrogen bonds with important residues in regulating enzyme activity (Ser152 and Phe77). Compound A14 showed high potency for further studies, such as the synthesis, in vitro and in vivo tests for pancreatic lipase inhibitory activity.

Atomistic structure of (Ba,Sr)TiO3: Comparing molecular-dynamics simulations with structural measurements

2013 ◽  
Vol 103 (2) ◽  
pp. 022909 ◽  
Author(s):  
M. J. Noordhoek ◽  
V. Krayzman ◽  
A. Chernatynskiy ◽  
S. R. Phillpot ◽  
I. Levin
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Dynamics Simulations ◽  
Atomistic Structure

scholarly journals An atomistic model for the thermal resistance of a liquid–solid interface

2022 ◽  
Vol 934 ◽  
Author(s):  
N.G. Hadjiconstantinou ◽  
M.M. Swisher
Keyword(s):  
Molecular Dynamics ◽  
Thermal Resistance ◽  
Heat Transport ◽  
Partial Evaluation ◽  
Quantitative Model ◽  
Point Of View ◽  
Atomistic Model ◽  
Level System ◽  
System Parameters ◽  
Dynamics Simulations

The thermal resistance associated with the interface between a solid and a liquid is analysed from an atomistic point of view. Partial evaluation of the associated Green–Kubo integral elucidates the various factors governing heat transport across the interface and leads to a quantitative model for the thermal resistance in terms of atomistic-level system parameters. The model is validated using molecular dynamics simulations.

scholarly journals In silico drug designing for COVID-19: an approach of highthroughput virtual screening, molecular and essential dynamics simulations

2020 ◽  
Author(s):  
Rakesh Kumar ◽  
Rahul Kumar ◽  
Pranay Tanwar
Keyword(s):  
Virtual Screening ◽  
Dynamics Simulation ◽  
Stable Complex ◽  
Binding Affinities ◽  
Essential Dynamics ◽  
Free Energies ◽  
Main Protease ◽  
Drug Designing ◽  
Dynamics Simulations ◽  
Potential Opportunity

Abstract SARS-CoV2, a new coronavirus has emerged in Wuhan city of China, December last year causing pneumonia named COVID-19 which has now spread to entire world. By April 2020, number of confirmed cumulative cases crossed ~2.4 million worldwide, according to WHO. Till date, no effective treatment or drug is available for this virus. Availability of X-ray structures of SARS-CoV2 main protease (Mpro) provided the potential opportunity for structure based drug designing. Here, we have made an attempt to do computational drug design by targeting main protease of SARS-CoV2. Highthroughput virtual screening of million molecules and natural compounds databases was performed followed by docking. Six ligands showed better binding affinities which were further optimized by MD simulation and rescoring of binding energy was calculated through MM/PBSA method. In addition, conformational effect of various ligands on protein was examined through essential dynamics simulation. Three compounds namely ZINC14732869, ZINC19774413 and ZINC19774479 were finally filtered that displayed high binding free energies than N3 inhibitor and form conformationally stable complex. Hence, current study features the discovery of novel inhibitors for main protease of CoV2 which will provide effective therapeutic candidates against COVID19.

scholarly journals Moving toward generalizable NZ-1 labeling for 3D structure determination with optimized epitope-tag insertion

2021 ◽  
Vol 77 (5) ◽  
pp. 645-662
Author(s):  
Risako Tamura-Sakaguchi ◽  
Rie Aruga ◽  
Mika Hirose ◽  
Toru Ekimoto ◽  
Takuya Miyake ◽  
...  
Keyword(s):  
Complex Formation ◽  
Structure Determination ◽  
Structural Changes ◽  
Insertion Site ◽  
3D Structure ◽  
Binding Pocket ◽  
Crystallographic Analysis ◽  
Stable Complex ◽  
X Ray Crystallography ◽  
Dynamics Simulations

Antibody labeling has been conducted extensively for structure determination using both X-ray crystallography and electron microscopy (EM). However, establishing target-specific antibodies is a prerequisite for applying antibody-assisted structural analysis. To expand the applicability of this strategy, an alternative method has been developed to prepare an antibody complex by inserting an exogenous epitope into the target. It has already been demonstrated that the Fab of the NZ-1 monoclonal antibody can form a stable complex with a target containing a PA12 tag as an inserted epitope. Nevertheless, it was also found that complex formation through the inserted PA12 tag inevitably caused structural changes around the insertion site on the target. Here, an attempt was made to improve the tag-insertion method, and it was consequently discovered that an alternate tag (PA14) could replace various loops on the target without inducing large structural changes. Crystallographic analysis demonstrated that the inserted PA14 tag adopts a loop-like conformation with closed ends in the antigen-binding pocket of the NZ-1 Fab. Due to proximity of the termini in the bound conformation, the more optimal PA14 tag had only a minor impact on the target structure. In fact, the PA14 tag could also be inserted into a sterically hindered loop for labeling. Molecular-dynamics simulations also showed a rigid structure for the target regardless of PA14 insertion and complex formation with the NZ-1 Fab. Using this improved labeling technique, negative-stain EM was performed on a bacterial site-2 protease, which enabled an approximation of the domain arrangement based on the docking mode of the NZ-1 Fab.

A Method for Identification of the Constitutive Law of Biological Filaments From Their Dynamic Equilibria

2015 ◽  
Author(s):  
Soheil Fatehiboroujeni ◽  
Sachin Goyal ◽  
Apostol Gramada
Keyword(s):  
Conformational Changes ◽  
Inverse Method ◽  
Vital Role ◽  
Constitutive Law ◽  
Cellular Processes ◽  
Inverse Approach ◽  
Double Stranded Dna ◽  
Dynamics Simulations ◽  
Dynamic Equilibria ◽  
Atomistic Structure

There are several biological filaments that play vital role in cellular processes via twisting and bending deformations. From the double-stranded DNA molecule containing genetic information to the cytoskeletal fibers that provide shape to the cell, biological filaments undergo conformational changes as they perform their biological tasks. Therefore the ability of a filament to deform, which depends on their atomistic structure, is a characteristic property that governs its biological functions. Since there is no direct analytic method to derive the deformability or constitutive law of such filaments from their atomistic structure, the constitutive law has to be identified from their actual deformations. An inverse approach based on a continuum rod model was developed recently that uses deformations in static equilibrium to estimate the constitutive law in bending and torsion. We extend the inverse method to use dynamic states of deformations, and consequently expand its scope to leverage a wide variety of choices in molecular dynamics simulations for identifying the constitutive law. This paper presents and validates the technique applying it to filaments with artificial atomistic structure.

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