The Myosin II Coiled-Coil Domain Atomic Structure in its Native Environment
| Autor: | J. Andrew McCammon, Dianne W. Taylor, Wen Ma, Hamidreza Rahmani, Kenneth A. Taylor, Thomas C. Irving, Robert J. Edwards, Zhongjun Hu, Nadia Daneshparvar |
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| Rok vydání: | 2021 |
| Předmět: |
Protein Conformation
alpha-Helical Cryo-electron microscopy Protein Conformation 1.1 Normal biological development and functioning invertebrate cryo-electron microscopy Crystal structure Molecular Dynamics Simulation Hemiptera Protein filament Underpinning research Myosin medicine Atomic model Animals Muscle Skeletal Instrumentation Myosin Type II Coiled coil Lethocerus indicus Multidisciplinary biology Chemistry C-terminus Cryoelectron Microscopy alpha-Helical Skeletal Biological Sciences biology.organism_classification filament striated muscle Biophysics Muscle Insect Proteins alpha helix coiled coil medicine.symptom Muscle contraction |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America, vol 118, iss 14 Proc Natl Acad Sci U S A |
| ISSN: | 1435-8115 1431-9276 |
| DOI: | 10.1017/s1431927621003299 |
| Popis: | The atomic structure of the complete myosin tail within thick filaments isolated from Lethocerus indicus flight muscle is described and compared to crystal structures of recombinant, human cardiac myosin tail segments. Overall, the agreement is good with three exceptions: the proximal S2, in which the filament has heads attached but the crystal structure doesn’t, and skip regions 2 and 4. At the head–tail junction, the tail α-helices are asymmetrically structured encompassing well-defined unfolding of 12 residues for one myosin tail, ∼4 residues of the other, and different degrees of α-helix unwinding for both tail α-helices, thereby providing an atomic resolution description of coiled-coil “uncoiling” at the head–tail junction. Asymmetry is observed in the nonhelical C termini; one C-terminal segment is intercalated between ribbons of myosin tails, the other apparently terminating at Skip 4 of another myosin tail. Between skip residues, crystal and filament structures agree well. Skips 1 and 3 also agree well and show the expected α-helix unwinding and coiled-coil untwisting in response to skip residue insertion. Skips 2 and 4 are different. Skip 2 is accommodated in an unusual manner through an increase in α-helix radius and corresponding reduction in rise/residue. Skip 4 remains helical in one chain, with the other chain unfolded, apparently influenced by the acidic myosin C terminus. The atomic model may shed some light on thick filament mechanosensing and is a step in understanding the complex roles that thick filaments of all species undergo during muscle contraction. |
| Databáze: | OpenAIRE |
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