REL RCSB RCSB RCSB 2015-09-09 2015-10-14 2015-12-16 2016-02-17 McCullough J Clippinger AK Talledge N Skowyra ML Saunders MG Naismith TV Colf LA Afonine P Arthur C Sundquist WI Hanson PI Frost A ESCRT-III, IST1, CHMP1B, membrane tubulation, helical filament McCullough J Clippinger AK Talledge N Skowyra ML Saunders MG Naismith TV Colf LA Afonine P Arthur C Sundquist WI Hanson PI Frost A SCIENCE 350 1548 1551 2015 26634441 doi:10.1126/science.aad8305 3jc1 FULLOVERLAP ESCRT-III copolymer of IST1 and CHMP1B ESCRT-III copolymer of IST1 and CHMP1B 2-stranded helical filament composed of one strand of IST1 subunits and one strand of CHMP1B subunits 2 IST1 Homo sapiens Human 0.022 0.022

IST1 N-terminal domain, residues 1-189

Polymer true Escherichia coli BL21 (RIPL) pGEX-2T-TEV P53990 Charged multivesicular body protein 1b Homo sapiens Human 0.022 0.022

full-length CHMP1B

Polymer true Escherichia coli BL21 (RIPL) pGEX-2T-TEV Q7LBR1 helical filament 0.7 8.0

25 mM Tris, 25 mM NaCl

3.5 uL of pelleted and resuspended liposome-nucleated IST1NTD-CHMP1B copolymers were applied to glow-discharged Quantifoil holey carbon grids (2 micron hole size, 2-4 micron spacing, 200 mesh).

ETHANE 100 FEI VITROBOT MARK I Blotted 7-9 seconds (-2 mm offset) and plunge-frozen FEI TECNAI F20 FLOOD BEAM BRIGHT FIELD FIELD EMISSION GUN 200 2.0 0.6 3.0 50000.0 GATAN LIQUID NITROGEN 2013-06-01 KODAK SO-163 FILM NIKON SUPER COOLSCAN 9000 2493 10

118,467 particles were selected from 2454 micrographs collected on a Titan Krios microscope with a Falcon I direct electron detector; 12,142 particles were selected from 39 micrographs collected on a JEM3200FSC microscope with a DE-12 direct electron detector.

FEI TITAN KRIOS FLOOD BEAM BRIGHT FIELD FIELD EMISSION GUN 300 0.6 3.0 59000.0 FEI TITAN KRIOS AUTOGRID HOLDER 2013-07-01 FEI FALCON I (4k x 4k) NIKON SUPER COOLSCAN 9000 2493 15

118,467 particles were selected from 2454 micrographs collected on a Titan Krios microscope with a Falcon I direct electron detector; 12,142 particles were selected from 39 micrographs collected on a JEM3200FSC microscope with a DE-12 direct electron detector.

JEOL 3200FSC FLOOD BEAM BRIGHT FIELD FIELD EMISSION GUN 300 3.40 0.6 3.0 59000.0 JEOL 3200FSC CRYOHOLDER 2013-08-01 DIRECT ELECTRON DE-12 (4k x 3k) NIKON SUPER COOLSCAN 9000 2493 20

118,467 particles were selected from 2454 micrographs collected on a Titan Krios microscope with a Falcon I direct electron detector; 12,142 particles were selected from 39 micrographs collected on a JEM3200FSC microscope with a DE-12 direct electron detector.

0 0

Particles were picked manually using the e2helixboxer.py function of EMAN2. Particles were aligned with IHRSR initially, followed by high resolution asymmetric refinement in RELION, followed by helical averaging in real space.

2.96 21.060 C1 4.0 OTHER CTFFIND3, EMAN2, IHRSR, SPIDER, RELION

51 copies (3 complete turns) of the asymmetric RELION reconstruction were transformed according to the helical symmetry, resampled on the original grid, and summed together, with Iterative Helical Real Space Reconstruction (IHRSR) single-particle algorithm as implemented in SPIDER and high-resolution refinement in RELION.

Each particle as implemented in RELION

3FRR A FLEXIBLE FIT Coot, Chimera, NAMD MDFF, Rosetta

3FRR was docked manually into the segmented density using Chimera. Regions with poor fit to density were identified using the Rosetta loops-from-density algorithm and iteratively fitted using alternating cycles of Rosetta's rebuild and refine protocol and manual refinement in Coot. The full ring of IST1 structures was then refined using Rosetta's symmetry constraints. Finally, backbone hydrogen bonds in the helical regions were constrained and two cycles of loop rebuilding with constraints were performed. The IST1 model was then combined with the CHMP1B model to form a heterodimer and this structure was refined by iterating between manual rebuilding and refinement using MDFF

Molprobity validation, cross-correlation REAL

emd_6461.png