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Matsudaira PT, Verma CS. Editorial. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 143:1-4. [PMID: 30951764 DOI: 10.1016/j.pbiomolbio.2019.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Paul T Matsudaira
- Department of Biological Science, National University of Singapore, 14 Science Drive 4, 117543, Singapore; Centre for BioImaging Sciences, National University of Singapore, 14 Science Drive 4, 117543, Singapore; MechanoBiology Institute, National University of Singapore, 5A Engineering Drive 1, 117411, Singapore.
| | - Chandra S Verma
- Department of Biological Science, National University of Singapore, 14 Science Drive 4, 117543, Singapore; School of Biological Sciences, Nanyang Technological University, 60 Nanyang Dr, 637551, Singapore; Bioinformatics Institute (A*STAR), 30 Biopolis Street, #07-01 Matrix, 138671, Singapore.
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SAXS-guided Enhanced Unbiased Sampling for Structure Determination of Proteins and Complexes. Sci Rep 2018; 8:17748. [PMID: 30531946 PMCID: PMC6288155 DOI: 10.1038/s41598-018-36090-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 11/12/2018] [Indexed: 02/08/2023] Open
Abstract
Molecular simulations can be utilized to predict protein structure ensembles and dynamics, though sufficient sampling of molecular ensembles and identification of key biologically relevant conformations remains challenging. Low-resolution experimental techniques provide valuable structural information on biomolecule at near-native conditions, which are often combined with molecular simulations to determine and refine protein structural ensembles. In this study, we demonstrate how small angle x-ray scattering (SAXS) information can be incorporated in Markov state model-based adaptive sampling strategy to enhance time efficiency of unbiased MD simulations and identify functionally relevant conformations of proteins and complexes. Our results show that using SAXS data combined with additional information, such as thermodynamics and distance restraints, we are able to distinguish otherwise degenerate structures due to the inherent ambiguity of SAXS pattern. We further demonstrate that adaptive sampling guided by SAXS and hybrid information can significantly reduce the computation time required to discover target structures. Overall, our findings demonstrate the potential of this hybrid approach in predicting near-native structures of proteins and complexes. Other low-resolution experimental information can be incorporated in a similar manner to collectively enhance unbiased sampling and improve the accuracy of structure prediction from simulation.
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Zhu G, Pan A, Grüber G, Lu L. Conformational states of Zika virus non-structural protein 3 determined by molecular dynamics simulations with small-angle X-Ray scattering data. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 143:13-19. [PMID: 30291845 DOI: 10.1016/j.pbiomolbio.2018.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 09/17/2018] [Accepted: 09/29/2018] [Indexed: 11/16/2022]
Abstract
Zika virus (ZIKV) has become a great public health emergency. Its non-structural protein 3 (NS3) is a key enzyme in viral replication and has been considered as a potential therapeutic target. A conformational characterization of ZIKV NS3 is critical for a comprehensive understanding of its molecular interactions and functions. However, the high conformational flexibility of solution NS3 obstacles the structural characterization of NS3 solely from the experimental observable that averages over its heterogeneous conformations. Here, we employed replica exchange with solute tempering (REST) method to simulate the di-domain protein ZIKV NS3. Three independent MD simulations identified a conserved conformational ensemble of NS3, consisting of a major conformational state and several minor states from compact to loose conformations. The major state agrees well with the scattering profile from small-angle X-ray scattering (SAXS) experiments. Moreover, the simulated ensemble is supported by a direct data-fitting result that requires both short- and long-range structural contacts to recover the experimental data. We discussed the interplay between simulation and experiment in ensemble construction of flexible biomolecules and shed light on the physically derived conformational ensembles.
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Affiliation(s)
- Guanhua Zhu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Ankita Pan
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Gerhard Grüber
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Lanyuan Lu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore.
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Zhu G, Liu W, Bao C, Tong D, Ji H, Shen Z, Yang D, Lu L. Investigating energy-based pool structure selection in the structure ensemble modeling with experimental distance constraints: The example from a multidomain protein Pub1. Proteins 2018; 86:501-514. [PMID: 29383828 DOI: 10.1002/prot.25468] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 12/26/2017] [Accepted: 01/23/2018] [Indexed: 12/25/2022]
Abstract
The structural variations of multidomain proteins with flexible parts mediate many biological processes, and a structure ensemble can be determined by selecting a weighted combination of representative structures from a simulated structure pool, producing the best fit to experimental constraints such as interatomic distance. In this study, a hybrid structure-based and physics-based atomistic force field with an efficient sampling strategy is adopted to simulate a model di-domain protein against experimental paramagnetic relaxation enhancement (PRE) data that correspond to distance constraints. The molecular dynamics simulations produce a wide range of conformations depicted on a protein energy landscape. Subsequently, a conformational ensemble recovered with low-energy structures and the minimum-size restraint is identified in good agreement with experimental PRE rates, and the result is also supported by chemical shift perturbations and small-angle X-ray scattering data. It is illustrated that the regularizations of energy and ensemble-size prevent an arbitrary interpretation of protein conformations. Moreover, energy is found to serve as a critical control to refine the structure pool and prevent data overfitting, because the absence of energy regularization exposes ensemble construction to the noise from high-energy structures and causes a more ambiguous representation of protein conformations. Finally, we perform structure-ensemble optimizations with a topology-based structure pool, to enhance the understanding on the ensemble results from different sources of pool candidates.
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Affiliation(s)
- Guanhua Zhu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
| | - Wei Liu
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore
| | - Chenglong Bao
- Department of Mathematics, National University of Singapore, 10 Lower Kent Ridge Road, Singapore, 119076, Singapore.,Yau Mathematical Sciences Center, Tsinghua University, Haidian District, Beijing, 100084, China
| | - Dudu Tong
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
| | - Hui Ji
- Department of Mathematics, National University of Singapore, 10 Lower Kent Ridge Road, Singapore, 119076, Singapore
| | - Zuowei Shen
- Department of Mathematics, National University of Singapore, 10 Lower Kent Ridge Road, Singapore, 119076, Singapore
| | - Daiwen Yang
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore
| | - Lanyuan Lu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
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Yang HC, Yang CH, Huang MY, Lu JF, Wang JS, Yeh YQ, Jeng US. Homology Modeling and Molecular Dynamics Simulation Combined with X-ray Solution Scattering Defining Protein Structures of Thromboxane and Prostacyclin Synthases. J Phys Chem B 2017; 121:11229-11240. [PMID: 29168638 DOI: 10.1021/acs.jpcb.7b08299] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A combination of molecular dynamics (MD) simulations and X-ray scattering (SAXS) has emerged as the approach of choice for studying protein structures and dynamics in solution. This approach has potential applications for membrane proteins that neither are soluble nor form crystals easily. We explore the water-coupled dynamic structures of thromboxane synthase (TXAS) and prostacyclin synthase (PGIS) from scanning HPLC-SAXS measurements combined with MD ensemble analyses. Both proteins are heme-containing enzymes in the cytochrome P450 family, known as prostaglandin H2 (PGH2) isomerase, with counter-functions in regulation of platelet aggregation. Currently, the X-ray crystallographic structures of PGIS are available, but those for TXAS are not. The use of homology modeling of the TXAS structure with ns-μs explicit water solvation MD simulations allows much more accurate estimation of the configuration space with loop motion and origin of the protein behaviors in solution. In contrast to the stability of the conserved PGIS structure in solution, the pronounced TXAS flexibility has been revealed to have unstructured loop regions in connection with the characteristic P450 structural elements. The MD-derived and experimental-solution SAXS results are in excellent agreement. The significant protein internal motions, whole-molecule structures, and potential problems with protein folding, crystallization, and functionality are examined.
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Affiliation(s)
- Hsiao-Ching Yang
- Department of Chemistry, Fu Jen Catholic University , New Taipei City 24205, Taiwan
| | - Cheng-Han Yang
- Department of Chemistry, Fu Jen Catholic University , New Taipei City 24205, Taiwan
| | - Ming-Yi Huang
- Department of Chemistry, Fu Jen Catholic University , New Taipei City 24205, Taiwan
| | - Jyh-Feng Lu
- School of Medicine, Fu Jen Catholic University , New Taipei City 24205, Taiwan
| | - Jinn-Shyan Wang
- School of Medicine, Fu Jen Catholic University , New Taipei City 24205, Taiwan
| | - Yi-Qi Yeh
- National Synchrotron Radiation Research Center , Hsinchu Science Park, Hsinchu 30076, Taiwan
| | - U-Ser Jeng
- National Synchrotron Radiation Research Center , Hsinchu Science Park, Hsinchu 30076, Taiwan.,Department of Chemical Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
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