REL PDBe PDBe PDBe 2016-01-18 2016-03-09 2016-10-05 2016-12-21 Hu Z Taylor DW Reedy MK Edwards RJ Taylor KA thick filament, insect fight muscle, myosin, paramyosin, myofilin, flightin, relaxed state, muscle contraction Hu Z Taylor DW Reedy MK Perz-Edwards RJ Taylor KA Sci. Adv. 2 2016 27704041 doi:10.1126/sciadv.1600058 Thick filament from Lethocerus (waterbug) flight muscle Thick filament from Lethocerus (waterbug) flight muscle

The sample is a bipolar helical structure, with helical repeat 145 Angstrom and helical turn 33.98 degree. The sample has C4 symmetry. The map contains 6 unique features: myosin molecule with completely resolved rods, 4 resolved non-myosin densities among the myosin rods and an annular region inside of annulus occupied by myosin rods that most likely contains paramyosin. The 4 non-myosin densities may contain parts of the proteins myofilin and flightin.

bipolar helical structure 4 myosin II Lethocerus indicus giant waterbug dorsal longitudinal indirect flight muscle myocyte sarcomere myofibril 0.52

The resolution of LMM and C-terminal of S2 domain is about 5.5 Angstrom; the N-terminal (at first crown) of S2 is about 7 angstrom; free head is about 10 angstrom; block head is about 20 angstrom.

Helical assembly false paramyosin Lethocerus indicus giant waterbug dorsal longitudinal indirect flight muscle myocyte sarcomere myofibril 0.1

Paramyosin is located in the filament core, and may not have the same symmetry with myosin. The resolution is lower at 10 Angstrom.

dimer false flightin Lethocerus indicus giant waterbug dorsal longitudinal indirect flight muscle myocyte sarcomere myofibril 0.019

We can see some non-myosin densities in the reconstruction. Their identification as flightin is uncertain

false Q5GMQ5 myofilin Lethocerus indicus giant waterbug dorsal longitudinal indirect flight muscle myocyte sarcomere myofibril 0.0303

We can see some non-myosin densities in the reconstruction. Their identification as myofilin is uncertain.

false Q70VH9 IPR031828 singleParticle filament 6.8

8 mM MOPS, 10 mM Na acetate, 1 mM Mg acetate, 1 mM ATP, and 1 mM EGTA

NEGATIVE

All reconstruction data obtained from unstained, frozen hydrated samples.

R2/1 Quantifoil grid

ETHANE 100 100 FEI VITROBOT MARK IV

The Vitrobot environmental chamber was set to 100% relative humidity for freezing and maintained at a temperature of 22 degrees Celsius. The crude filament prep was applied to the grid, incubated for 60 seconds, blotted once and then plunged into liquid ethane to vitrify.

EM samples of relaxed filaments were prepared by applying 4 microliters of the above prep to a R2/1 Quantifoil grid at room temperature for 1 minute, washing with several drops of rinse buffer, identical to the relaxing buffer except NaCl was replaced with Na acetate. Following a 2 minute incubation, the grid was washed with several drops of a low salt rinse consisting of 8 mM MOPS, 10 mM Na Acetate, 1 mM Mg Acetate, 1 mM ATP, and 1 mM EGTA, pH 6.8. FEI TITAN KRIOS FLOOD BEAM BRIGHT FIELD FIELD EMISSION GUN 300 2.7 1.5 2.5 29000.0 FEI TITAN KRIOS AUTOGRID HOLDER 90

48 frames were recorded over a 1.5 sec exposure time

2015-03-27 OTHER 4000 65

The total dose is 65 electrons with 48 frames

32.

Particles are picked and segmented using Appion system. The defocus was determined and refined using ACE and CTFFIND3. The 3D classification and final reconstruction was performed by RELION.

Each particle

145 33.98 C4 OTHER 5.5 OTHER Relion

Damage compensation strategy was used after whole frame alignment. There were 72,000 segments at beginning. After 3D classification, only 24,000 segments were used in the final reconstruction.

24000

The limit of angle tilt is 75 degrees

emd_3301.png

emd_3301_fsc.xml