scholarly journals Signature of N-terminal domain (NTD) structural re-orientation in NPC1 for proper alignment of cholesterol transport: Molecular dynamics study with mutation

2020 ◽  
Author(s):  
Hye-Jin Yoon ◽  
Hyunah Jeong ◽  
Hyung Ho Lee ◽  
Soonmin Jang
Keyword(s):  
Molecular Dynamics ◽  
Full Length ◽  
Cholesterol Transport ◽  
Cholesterol Trafficking ◽  
Terminal Domain ◽  
Loop Region ◽  
Niemann Pick ◽  
Dynamics Simulations ◽  
And Function ◽  
Lumenal Domain

AbstractThe lysosomal membrane protein NPC1 (Niemann-Pick type C1) and NPC2 (Niemann-Pick type C2) are main players of cholesterol control in lysosome and it is known that mutation on these proteins leads to cholesterol trafficking related disease, called Niemann-Pick disease type C (NPC) disease. The mutation R518W or R518Q on NPC1 is one of such disease-related mutations, causing reduced cholesterol transport by half, resulting in accumulation of cholesterol and lipids in late endosomal/lysosomal region of the cell. Even though there has been significant progress in understanding cholesterol transport by NPC1 in combination with NPC2, especially after the structural determination of full length NPC1 in 2016, many details such as interaction of full length NPC1 with NPC2, molecular motions responsible for cholesterol transport during and after this interaction, and structure and function relations of many mutations are still not well understood.We report the extensive molecular dynamics simulations to gain insight into the structure and motions of NPC1 lumenal domain for cholesterol transport and disease behind the mutation (R518W). It is found that the mutation induces structural shift of NTD (N-terminal domain), toward the loop region in MLD (middle lumenal domain), which is believed to play central role in interaction with NPC2 protein, such that the interaction with NPC2 protein might be less favorable compare to wild NPC1. Also, the simulation indicates the possible re-orientation of the NTD, aligning to form an internal tunnel, after receiving the cholesterol from NPC2 with wild NPC1 unlike the mutated one, a possible pose for further action in cholesterol trafficking. We believe the current study can provide better understanding on the cholesterol transport by NPC1, especially the role of NTD of NPC1, in combination with NPC2 interaction.Synopsismodeling study of cholesterol binding protein NPC1

scholarly journals Lysosomal cholesterol export reconstituted from fragments of Niemann-Pick C1

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Michael Nguyen Trinh ◽  
Michael S Brown ◽  
Joachim Seemann ◽  
Joseph L Goldstein ◽  
Feiran Lu
Keyword(s):  
Membrane Protein ◽  
Lipid Bilayer ◽  
Full Length ◽  
Cholesterol Transport ◽  
Transmembrane Helices ◽  
Terminal Domain ◽  
Data Support ◽  
Covalently Linked ◽  
Niemann Pick ◽  
Polytopic Membrane Protein

Niemann-Pick C1 (NPC1) is a polytopic membrane protein with 13 transmembrane helices that exports LDL-derived cholesterol from lysosomes by carrying it through the 80 Å glycocalyx and the 40 Å lipid bilayer. Transport begins when cholesterol binds to the N-terminal domain (NTD) of NPC1, which projects to the surface of the glycocalyx. Here, we reconstitute cholesterol transport by expressing the NTD as a fragment separate from the remaining portion of NPC1. When co-expressed, the two NPC1 fragments reconstitute cholesterol transport, indicating that the NTD has the flexibility to interact with the remaining parts of NPC1 even when not covalently linked. We also show that cholesterol can be transferred from the NTD of one full-length NPC1 to another NPC1 molecule that lacks the NTD. These data support the hypothesis that cholesterol is transported through interactions between two or more NPC1 molecules.

scholarly journals Protein unfolding by SDS: the microscopic mechanisms and the properties of the SDS-protein assembly

Nanoscale ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 5422-5434 ◽  
Author(s):  
David Winogradoff ◽  
Shalini John ◽  
Aleksei Aksimentiev
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Anionic Surfactant ◽  
Protein Unfolding ◽  
Protein Assembly ◽  
Full Length ◽  
Dynamics Simulations

Molecular dynamics simulations reveal how anionic surfactant SDS and heat unfold full-length proteins.

Abstract 42: Differential Contribution Of The N- And C-terminal Domains To The Folding And Function Of Tandem Calponin-homology Domains

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Krishna Mallela ◽  
Swati Bandi ◽  
Surinder Singh ◽  
Geoffrey Armstrong
Keyword(s):  
Full Length ◽  
Actin Binding ◽  
Main Function ◽  
Calponin Homology ◽  
Terminal Domain ◽  
Binding Domains ◽  
Binding Function ◽  
Ch2 Domain ◽  
The Stability ◽  
And Function

Tandem calponin-homology (CH) domains constitute a major class of actin-binding domains that include dystrophin and utrophin, the two key proteins involved in muscular dystrophy. Despite their importance, how their structure controls their function is not understood. Here, we study the contribution of individual CH domains to the actin-binding function and thermodynamic stability of utrophin’s tandem CH domain. Traditional actin co-sedimentation assays indicate that the isolated C-terminal CH2 domain binds weakly to F-actin when compared with the full-length tandem CH domain. In contrast, isolated CH1 binds to F-actin with a similar efficiency as that of the full-length tandem CH domain. Thus, the obvious question that arises is why tandem CH domains require CH2, when their actin-binding efficiency is originating primarily from CH1. To answer, we probed the thermodynamic stabilities of individual CH domains. Isolated CH1 domain is unstable and is prone to serious aggregation. Isolated CH2 is very stable, even appears to be more stable than the full-length tandem CH domain. In addition, the CH2 domain, which is more stable, is less functional. These results indicate that the main function of CH2 is to stabilize CH1. Consistently, the proposed structure of utrophin’s tandem CH domain based on earlier X-ray studies indicates a close proximity between the C-terminal helix of CH2 and the N-terminal helix of CH1, and this helix in CH2 is more dynamic in the full-length protein when compared with that in the absence of CH1, suggesting the mechanism by which CH2 stabilizes CH1. These observations indicate that the two CH domains contribute differentially to the folding and function of tandem CH domains, although both domains essentially have the same native structure in the tandem CH domain. The N-terminal domain determines the function, whereas the C-terminal domain determines the stability. This work was funded by the AHA Grant 11SDG4880046.

The Fats of Life: Using Computational Chemistry to Characterise the Eukaryotic Cell Membrane

2020 ◽  
Vol 73 (3) ◽  
pp. 85 ◽  
Author(s):  
Katie A. Wilson ◽  
Lily Wang ◽  
Hugo MacDermott-Opeskin ◽  
Megan L. O'Mara
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Lipid Bilayers ◽  
Current Knowledge ◽  
Computational Modelling ◽  
Eukaryotic Cell ◽  
Computational Techniques ◽  
Lipid Species ◽  
Dynamics Simulations ◽  
And Function

Our current knowledge of the structural dynamics and complexity of lipid bilayers is still developing. Computational techniques, especially molecular dynamics simulations, have increased our understanding significantly as they allow us to model functions that cannot currently be experimentally resolved. Here we review available computational tools and techniques, the role of the major lipid species, insights gained into lipid bilayer structure and function from molecular dynamics simulations, and recent progress towards the computational modelling of the physiological complexity of eukaryotic lipid bilayers.

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