Allosteric Modulation of Human Hsp90α Conformational Dynamics:
- Authors: Penkler, David L , Atilgan, Canan , Tastan Bishop, Özlem
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/162936 , vital:40998 , https://doi.org/10.1021/acs.jcim.7b00630
- Description: Central to Hsp90’s biological function is its ability to interconvert between various conformational states. Drug targeting of Hsp90’s regulatory mechanisms, including its modulation by cochaperone association, presents as an attractive therapeutic strategy for Hsp90 associated pathologies. In this study, we utilized homology modeling techniques to calculate full-length structures of human Hsp90α in closed and partially open conformations and used these structures as a basis for several molecular dynamics based analyses aimed at elucidating allosteric mechanisms and modulation sites in human Hsp90α.
- Full Text:
- Date Issued: 2018
MODE-TASK: Large-scale protein motion tools
- Authors: Ross, Caroline J , Nizami, B , Glenister, Michael , Amamuddy, Olivier S , Atilgan, Ali R , Atilgan, Canan , Tastan Bishop, Özlem
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125206 , vital:35746 , http://dx.doi.org/10.1101/217505
- Description: Conventional analysis of molecular dynamics (MD) trajectories may not identify global motions of macromolecules. Normal Mode Analysis (NMA) and Principle Component Analysis (PCA) are two popular methods to quantify large-scale motions, and find the “essential motions”; and have been applied to problems such as drug resistant mutations (Nizami et al., 2016) and viral capsid expansion (Hsieh et al., 2016). MODE-TASK is an array of tools to analyse and compare protein dynamics obtained from MD simulations and/or coarse grained elastic network models. Users may perform standard PCA, kernel and incremental PCA (IPCA). Data reduction techniques (Multidimensional Scaling (MDS) and t-Distributed Stochastics Neighbor Embedding (t-SNE)) are implemented. Users may analyse normal modes by constructing elastic network models (ENMs) of a protein complex. A novel coarse graining approach extends its application to large biological assemblies.
- Full Text:
- Date Issued: 2018
Unraveling the Motions behind Enterovirus 71 Uncoating:
- Authors: Ross, Caroline J , Atilgan, Ali R , Tastan Bishop, Özlem , Atilgan, Canan
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148158 , vital:38715 , DOI: 10.1016/j.bpj.2017.12.021
- Description: Enterovirus 71 can be a severe pathogen in small children and immunocompromised adults. Virus uncoating is a critical step in the infection of the host cell; however, the mechanisms that control this process remain poorly understood. We applied normal mode analysis and perturbation response scanning to several complexes of the virus capsid and present a coarse-graining approach to analyze the full capsid. We show that our method offers an alternative to expressing the system as a set of rigid blocks and accounts for the interconnection between nodes within each subunit and protein interfaces across the capsid. In our coarse-grained approach, the modes associated with capsid expansion are captured in the first three nondegenerate modes and correspond to the changes observed in structural studies of the virus. We show that the resolution of the analysis may be modified without losing information on the global motions leading to uncoating.
- Full Text:
- Date Issued: 2018
Allosteric modulation of conformational dynamics in human Hsp90α: a computational study
- Authors: Penkler, David L , Atilgan, Canan , Tastan Bishop, Özlem
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68531 , vital:29276 , http://dx.doi.org/10.1101/198341
- Description: Central to Hsp90’s biological function is its ability to interconvert between various conformational states. Drug targeting of Hsp90’s regulatory mechanisms, including its modulation by co-chaperone association, presents as an attractive therapeutic strategy for Hsp90 associated pathologies. Here, we utilize homology modeling techniques to calculate full-length structures of human Hsp90α in closed and partially-open conformations. Atomistic simulations of these structures demonstrated that bound ATP stabilizes the dimer by ‘tensing’ each protomer, while ADP and apo configurations ‘relax’ the complex by increasing global flexibility. Dynamic residue network analysis revealed regions of the protein involved in intra-protein communication, and identified several overlapping key communication hubs that correlate with known functional sites. Perturbation response scanning analysis identified several potential residue sites capable of modulating conformational change in favour of interstate conversion. For the ATP-bound open conformation, these sites were found to overlap with known Aha1 and client binding sites, demonstrating how naturally occurring forces associated with co-factor binding could allosterically modulate conformational dynamics.
- Full Text:
- Date Issued: 2017
MD-TASK: a software suite for analyzing molecular dynamics trajectories
- Authors: Brown, David K , Penkler, David L , Amamuddy, Olivier S , Ross, Caroline J , Atilgan, Ali R , Atilgan, Canan , Tastan Bishop, Özlem
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125138 , vital:35735 , https://doi.10.1093/bioinformatics/btx349
- Description: Molecular dynamics (MD) determines the physical motions of atoms of a biological macromolecule in a cell-like environment and is an important method in structural bioinformatics. Traditionally, measurements such as root mean square deviation, root mean square fluctuation, radius of gyration, and various energy measures have been used to analyze MD simulations. Here, we present MD-TASK, a novel software suite that employs graph theory techniques, perturbation response scanning, and dynamic cross-correlation to provide unique ways for analyzing MD trajectories.
- Full Text:
- Date Issued: 2017
Perturbation–Response Scanning reveals key residues for Allosteric Control in Hsp70:
- Authors: Penkler, David L , Sensoy, Özge , Atilgan, Canan , Tastan Bishop, Özlem
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148195 , vital:38718 , DOI: 10.1021/acs.jcim.6b00775
- Description: Hsp70 molecular chaperones play an important role in maintaining cellular homeostasis, and are implicated in a wide array of cellular processes, including protein recovery from aggregates, cross-membrane protein translocation, and protein biogenesis. Hsp70 consists of two domains, a nucleotide binding domain (NBD) and a substrate binding domain (SBD), each of which communicates via an allosteric mechanism such that the protein interconverts between two functional states, an ATP-bound open conformation and an ADP-bound closed conformation. The exact mechanism for interstate conversion is not as yet fully understood. However, the ligand-bound states of the NBD and SBD as well as interactions with cochaperones such as DnaJ and nucleotide exchange factor are thought to play crucial regulatory roles. In this study, we apply the perturbation–response scanning (PRS) method in combination with molecular dynamics simulations as a computational tool for the identification of allosteric hot residues in the large multidomain Hsp70 protein.
- Full Text:
- Date Issued: 2017