1O18

MOLECULAR MODELS OF AVERAGED RIGOR CROSSBRIDGES FROM TOMOGRAMS OF INSECT FLIGHT MUSCLE


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 70.0 Å
  • Aggregation State: TISSUE 
  • Reconstruction Method: TOMOGRAPHY 

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This is version 1.5 of the entry. See complete history


Literature

Molecular Modeling of Averaged Rigor Crossbridges from Tomograms of Insect Flight Muscle

Chen, L.F.Winkler, H.Reedy, M.K.Reedy, M.C.Taylor, K.A.

(2002) J Struct Biol 138: 92

  • DOI: https://doi.org/10.1016/s1047-8477(02)00013-8
  • Primary Citation of Related Structures:  
    1M8Q, 1MVW, 1O18, 1O19, 1O1A, 1O1B, 1O1C, 1O1D, 1O1E, 1O1F, 1O1G

  • PubMed Abstract: 

    Electron tomography, correspondence analysis, molecular model building, and real-space refinement provide detailed 3-D structures for in situ myosin crossbridges in the nucleotide-free state (rigor), thought to represent the end of the power stroke. Unaveraged tomograms from a 25-nm longitudinal section of insect flight muscle preserved native structural variation. Recurring crossbridge motifs that repeat every 38.7 nm along the actin filament were extracted from the tomogram and classified by correspondence analysis into 25 class averages, which improved the signal to noise ratio. Models based on the atomic structures of actin and of myosin subfragment 1 were rebuilt to fit 11 class averages. A real-space refinement procedure was applied to quantitatively fit the reconstructions and to minimize steric clashes between domains introduced during the fitting. These combined procedures show that no single myosin head structure can fit all the in situ crossbridges. The validity of the approach is supported by agreement of these atomic models with fluorescent probe data from vertebrate muscle as well as with data from regulatory light chain crosslinking between heads of smooth muscle heavy meromyosin when bound to actin.


  • Organizational Affiliation

    Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
SKELETAL MUSCLE MYOSIN II840Gallus gallusMutation(s): 0 
UniProt
Find proteins for P13538 (Gallus gallus)
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Go to UniProtKB:  P13538
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UniProt GroupP13538
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
SKELETAL MUSCLE MYOSIN II REGULATORY LIGHT CHAINC [auth E],
F [auth H],
I [auth K],
L [auth N],
O [auth Q]
145Gallus gallusMutation(s): 0 
UniProt
Find proteins for P02609 (Gallus gallus)
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Go to UniProtKB:  P02609
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UniProt GroupP02609
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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
SKELETAL MUSCLE MYOSIN II ESSENTIAL LIGHT CHAIND [auth F],
G [auth I],
J [auth L],
M [auth O],
P [auth R]
147Gallus gallusMutation(s): 0 
UniProt
Find proteins for P02605 (Gallus gallus)
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UniProt GroupP02605
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Entity ID: 4
MoleculeChains Sequence LengthOrganismDetailsImage
SKELETAL MUSCLE ACTIN375Oryctolagus cuniculusMutation(s): 0 
UniProt
Find proteins for P68135 (Oryctolagus cuniculus)
Explore P68135 
Go to UniProtKB:  P68135
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UniProt GroupP68135
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  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
MLY
Query on MLY
A
B [auth D]
E [auth G]
H [auth J]
K [auth M]
A,
B [auth D],
E [auth G],
H [auth J],
K [auth M],
N [auth P]
L-PEPTIDE LINKINGC8 H18 N2 O2LYS
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 70.0 Å
  • Aggregation State: TISSUE 
  • Reconstruction Method: TOMOGRAPHY 
EM Software:
TaskSoftware PackageVersion
RECONSTRUCTIONCustom

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2002-11-27
    Type: Initial release
  • Version 1.1: 2008-04-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-07-18
    Changes: Data collection
  • Version 1.4: 2019-11-06
    Changes: Advisory, Data collection, Derived calculations, Other
  • Version 1.5: 2023-12-27
    Changes: Data collection, Database references, Derived calculations, Refinement description