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Title | D-loop Dynamics and Near-Atomic-Resolution Cryo-EM Structure of Phalloidin-Bound F-Actin. |
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Journal, issue, pages | Structure, Vol. 28, Issue 5, Page 586-593.e3, Year 2020 |
Publish date | May 5, 2020 |
Authors | Sanchaita Das / Peng Ge / Zeynep A Oztug Durer / Elena E Grintsevich / Z Hong Zhou / Emil Reisler / |
PubMed Abstract | Detailed molecular information on G-actin assembly into filaments (F-actin), and their structure, dynamics, and interactions, is essential for understanding their cellular functions. Previous studies ...Detailed molecular information on G-actin assembly into filaments (F-actin), and their structure, dynamics, and interactions, is essential for understanding their cellular functions. Previous studies indicate that a flexible DNase I binding loop (D-loop, residues 40-50) plays a major role in actin's conformational dynamics. Phalloidin, a "gold standard" for actin filament staining, stabilizes them and affects the D-loop. Using disulfide crosslinking in yeast actin D-loop mutant Q41C/V45C, light-scattering measurements, and cryoelectron microscopy reconstructions, we probed the constraints of D-loop dynamics and its contribution to F-actin formation/stability. Our data support a model of residues 41-45 distances that facilitate G- to F-actin transition. We report also a 3.3-Å resolution structure of phalloidin-bound F-actin in the ADP-Pi-like (ADP-BeFx) state. This shows the phalloidin-binding site on F-actin and how the relative movement between its two protofilaments is restricted by it. Together, our results provide molecular details of F-actin structure and D-loop dynamics. |
External links | Structure / PubMed:32348747 / PubMed Central |
Methods | EM (helical sym.) |
Resolution | 3.8 Å |
Structure data | EMDB-20694, PDB-6u96: |
Chemicals | ChemComp-ADP: |
Source |
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Keywords | STRUCTURAL PROTEIN / Actin / phalloidin / beryllium fluoride |