scholarly journals Polysulfates Block SARS-CoV-2 Uptake via Electrostatic Interactions

Author(s):  
Chuanxiong Nie ◽  
Paria Pouyan ◽  
Daniel Lauster ◽  
Jakob Trimpert ◽  
Yannic Kerkhoff ◽  
...  

<p><a>Here we report that negatively charged polysulfates can bind to the spike protein of SARS-CoV-2 via electrostatic interactions</a>. Using a plaque reduction assay, we compare inhibition of SARS-CoV-2 by heparin, pentosan sulfate, linear polyglycerol sulfate (LPGS) and hyperbranched polyglycerol sulfate (HPGS). Highly sulfated LPGS is the optimal inhibitor, with a half-maximal inhibitory concentration (IC<sub>50</sub>) of 67 μg/mL (approx. 1.6 μM). This synthetic polysulfates exhibit more than 60-fold higher virus inhibitory activity than heparin (IC<sub>50</sub>: 4084 μg/mL), along with much lower anticoagulant activity. Furthermore, in molecular dynamics simulations, we verified that LPGS can bind stronger to the spike protein than heparin, and that LPGS can interact even more with the spike protein of the new N501Y and E484K variants. Our study demonstrates that the entry of SARS-CoV-2 into host cells can be blocked via electrostatic interaction, therefore LPGS can serve as a blueprint for the design of novel viral inhibitors of SARS-CoV-2. </p>

2021 ◽  
Author(s):  
Chuanxiong Nie ◽  
Paria Pouyan ◽  
Daniel Lauster ◽  
Jakob Trimpert ◽  
Yannic Kerkhoff ◽  
...  

<p><a>Here we report that negatively charged polysulfates can bind to the spike protein of SARS-CoV-2 via electrostatic interactions</a>. Using a plaque reduction assay, we compare inhibition of SARS-CoV-2 by heparin, pentosan sulfate, linear polyglycerol sulfate (LPGS) and hyperbranched polyglycerol sulfate (HPGS). Highly sulfated LPGS is the optimal inhibitor, with a half-maximal inhibitory concentration (IC<sub>50</sub>) of 67 μg/mL (approx. 1.6 μM). This synthetic polysulfates exhibit more than 60-fold higher virus inhibitory activity than heparin (IC<sub>50</sub>: 4084 μg/mL), along with much lower anticoagulant activity. Furthermore, in molecular dynamics simulations, we verified that LPGS can bind stronger to the spike protein than heparin, and that LPGS can interact even more with the spike protein of the new N501Y and E484K variants. Our study demonstrates that the entry of SARS-CoV-2 into host cells can be blocked via electrostatic interaction, therefore LPGS can serve as a blueprint for the design of novel viral inhibitors of SARS-CoV-2. </p>


2021 ◽  
Vol 8 ◽  
Author(s):  
Sugunadevi Sakkiah ◽  
Wenjing Guo ◽  
Bohu Pan ◽  
Zuowei Ji ◽  
Gokhan Yavas ◽  
...  

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19). As of October 21, 2020, more than 41.4 million confirmed cases and 1.1 million deaths have been reported. Thus, it is immensely important to develop drugs and vaccines to combat COVID-19. The spike protein present on the outer surface of the virion plays a major role in viral infection by binding to receptor proteins present on the outer membrane of host cells, triggering membrane fusion and internalization, which enables release of viral ssRNA into the host cell. Understanding the interactions between the SARS-CoV-2 trimeric spike protein and its host cell receptor protein, angiotensin converting enzyme 2 (ACE2), is important for developing drugs and vaccines to prevent and treat COVID-19. Several crystal structures of partial and mutant SARS-CoV-2 spike proteins have been reported; however, an atomistic structure of the wild-type SARS-CoV-2 trimeric spike protein complexed with ACE2 is not yet available. Therefore, in our study, homology modeling was used to build the trimeric form of the spike protein complexed with human ACE2, followed by all-atom molecular dynamics simulations to elucidate interactions at the interface between the spike protein and ACE2. Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA) and in silico alanine scanning were employed to characterize the interacting residues at the interface. Twenty interacting residues in the spike protein were identified that are likely to be responsible for tightly binding to ACE2, of which five residues (Val445, Thr478, Gly485, Phe490, and Ser494) were not reported in the crystal structure of the truncated spike protein receptor binding domain (RBD) complexed with ACE2. These data indicate that the interactions between ACE2 and the tertiary structure of the full-length spike protein trimer are different from those between ACE2 and the truncated monomer of the spike protein RBD. These findings could facilitate the development of drugs and vaccines to prevent SARS-CoV-2 infection and combat COVID-19.


2021 ◽  
Author(s):  
Yihan Huang ◽  
Bradley S Harris ◽  
Shiaki A Minami ◽  
Seongwon Jung ◽  
Priya Shah ◽  
...  

Highly detailed steered Molecular Dynamics simulations are performed on differently glycosylated receptor binding domains of the SARS-CoV-2 spike protein. The binding strength and the binding range increases with glycosylation. The interaction energy rises very quickly with pulling the proteins apart and only slowly drops at larger distances. We see a catch slip type behavior where interactions during pulling break and are taken over by new interactions forming. The dominant interaction mode are hydrogen bonds but Lennard-Jones and electrostatic interactions are relevant as well.


2021 ◽  
Author(s):  
Soumya Lipsa Rath ◽  
Madhusmita Tripathy ◽  
Nabanita Mandal

Enveloped viruses, in general, have several transmembrane proteins and glycoproteins, which assist the virus in entry and attachment onto the host cells. These proteins also play a significant role in determining the shape and size of the newly formed virus particles. The lipid membrane and the embedded proteins affect each other in non-trivial ways during the course of the viral life cycle. Unravelling the nature of the protein-protein and protein-lipid interactions, under various environmental and physiological conditions, could therefore prove to be crucial in development of therapeutics. Here, we study the M protein of SARS-CoV-2 to understand the effect of temperature on the properties of the protein-membrane system. The membrane embedded dimeric M proteins were studied using atomistic and coarse-grained molecular dynamics simulations at temperatures ranging between 10 and 50 ˚C. While temperature induced fluctuations should be monotonic, we observe a steady rise in the protein dynamics up to 40 ˚C, beyond which it surprisingly reverts back to the low temperature behaviour. Detailed investigation reveals disordering of the membrane lipids in the presence of the protein, which induces additional curvature around the transmembrane region. Coarse-grained simulations indicate temperature dependent aggregation of M protein dimers. Our study clearly indicates that the dynamics of membrane lipids and integral M protein of SARS-CoV-2 enables it to better associate and aggregate only at a certain temperature range (i.e., ~30 to 40 ˚C). This can have important implications in the protein aggregation and subsequent viral budding/fission processes.   


2019 ◽  
Vol 24 (9) ◽  
pp. 928-938 ◽  
Author(s):  
Luca Palazzolo ◽  
Chiara Paravicini ◽  
Tommaso Laurenzi ◽  
Sara Adobati ◽  
Simona Saporiti ◽  
...  

SLC6A14 (ATB0,+) is a sodium- and chloride-dependent neutral and dibasic amino acid transporter that regulates the distribution of amino acids across cell membranes. The transporter is overexpressed in many human cancers characterized by an increased demand for amino acids; as such, it was recently acknowledged as a novel target for cancer therapy. The knowledge on the molecular mechanism of SLC6A14 transport is still limited, but some elegant studies on related transporters report the involvement of the 12 transmembrane α-helices in the transport mechanism, and describe structural rearrangements mediated by electrostatic interactions with some pivotal gating residues. In the present work, we constructed a SLC6A14 model in outward-facing conformation via homology modeling and used molecular dynamics simulations to predict amino acid residues critical for substrate recognition and translocation. We docked the proteinogenic amino acids and other known substrates in the SLC6A14 binding site to study both gating regions and the exposed residues involved in transport. Interestingly, some of these residues correspond to those previously identified in other LeuT-fold transporters; however, we could also identify a novel relevant residue with such function. For the first time, by combined approaches of molecular docking and molecular dynamics simulations, we highlight the potential role of these residues in neutral amino acid transport. This novel information unravels new aspects of the human SLC6A14 structure–function relationship and may have important outcomes for cancer treatment through the design of novel inhibitors of SLC6A14-mediated transport.


2019 ◽  
Author(s):  
Qiang Shao ◽  
Jinan Wang ◽  
Weiliang Zhu

AbstractIn this work, the combined influence of urea and KI on protein native structure is quantitatively investigated through the comparative molecular dynamics simulations on the structural dynamics of a polypeptide of TRPZIP4 in a series of urea/KI mixed solutions (urea concentration: 4M, KI salt concentration: 0M-6M). The observed enhanced denaturing ability of urea/KI mixture can be explained by direct interactions of urea/K+/water towards protein (electrostatic and vdW interactions from urea and electrostatic interactions from K+ and water) and indirect influence of KI on the strengthened interaction of urea towards protein backbone and side-chain. The latter indirect influence is fulfilled through the weakening of hydrogen bonding network among urea and water by the appearance of K+–water and I—urea interactions. As a result, the denaturing ability enhancement of urea and KI mixed solution is induced by the collaborative behavior of urea and KI salt.


2018 ◽  
Author(s):  
Annie M. Westerlund ◽  
Lucie Delemotte

AbstractCalmodulin (CaM) is a calcium sensing protein that regulates the function of a large number of proteins, thus playing a crucial part in many cell signaling path- ways. CaM has the ability to bind more than 300 different target peptides in a Ca2+-dependent manner, mainly through the exposure of hydrophobic residues. How CaM can bind a large number of targets while retaining some selectivity is a fascinating open question.Here, we explore the mechanism of CaM selective promiscuity for selected target proteins. Analyzing enhanced sampling molecular dynamics simulations of Ca2+-bound and Ca2+-free CaM via spectral clustering has allowed us to identify distinct conformational states, characterized by interhelical angles, secondary structure determinants and the solvent exposure of specific residues. We searched for indicators of conformational selection by mapping solvent exposure of residues in these conformational states to contacts in structures of CaM/target peptide complexes. We thereby identified CaM states involved in various binding classes arranged along a depth binding gradient. Binding Ca2+ modifies the accessible hydrophobic surface of the two lobes and allows for deeper binding. Apo CaM indeed shows shallow binding involving predominantly polar and charged residues. Furthermore, binding to the C-terminal lobe of CaM appears selective and involves specific conformational states that can facilitate deep binding to target proteins, while binding to the N-terminal lobe appears to happen through a more flexible mechanism. Thus the long-ranged electrostatic interactions of the charged residues of the N-terminal lobe of CaM may initiate binding, while the short-ranged interactions of hydrophobic residues in the C-terminal lobe of CaM may account for selectivity.This work furthers our understanding of the mechanism of CaM binding and selectivity to different target proteins and paves the way towards a comprehensive model of CaM selectivity.Author summaryCalmodulin is a protein involved in the regulation of a variety of cell signaling pathways. It acts by making usually calcium-insensitive proteins sensitive to changes in the calcium concentration inside the cell. Its two lobes bind calcium and allow the energetically unfavorable exposure of hydrophobic residues to the aqueous environment which can then bind target proteins. The mechanisms behind the simultaneous specificity and variation of target protein binding is yet unknown but will aid understanding of the calcium-signaling and regulation that occur in many of our cellular processes.Here, we used molecular dynamics simulations and data analysis techniques to investigate what effect calcium has on the binding modes of calmodulin. The simulations and analyses allow us to observe and differentiate specific states. One domain of calmodulin is shown to be selective with binding involving short- distance interactions between hydrophobic residues, while the other binds target proteins through a more flexible mechanism involving long-distance electrostatic interactions.


Author(s):  
Liping Zhou ◽  
Leyun Wu ◽  
Cheng Peng ◽  
Yanqing Yang ◽  
Yulong Shi ◽  
...  

The coronavirus disease 2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Among all the potential targets studied for developing drugs and antibodies, the spike (S)...


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