2017-11-08 REL PDBe PDBe PDBe 2017-08-13 2017-10-18 2017-10-18 2017-11-08 Elad N Bellapadrona G Houben L Sagi I Elbaum M Elad N Bellapadrona G Houben L Sagi I Elbaum M Proc. Natl. Acad. Sci. U.S.A. US 114 11139 11144 2017 28973937 doi:10.1073/pnas.1708609114 1091-6490 0040 PNASA6 EMD-3849 other EM volume

Contains ferritin with Fe at low stoichiometry reconstructed from cryo-STEM images

EMD-3848 associated EM volume Human heavy chain ferritin with Zn Human heavy chain ferritin with Zn 0 1

Bacterially expressed and purified human heavy chain ferritin mixed with a 48 fold molar excess of Zn(II)SO4

Homo sapiens Escherichia coli 0.504 singleParticle particle 0.13 7.2 50.0 HEPES-NaOH 0.2 NaCl Quantifoil R2/1 COPPER 200 CARBON HOLEY CARBON CONTINUOUS GLOW DISCHARGE AIR ETHANE 95 297 LEICA EM GP

For metal loading, stock protein (2.9 mg/ml) was diluted to 0.25 mg/ml and mixed with a 48 fold molar excess of Zn(II)SO4.

FEI TECNAI 20 OTHER DARK FIELD FIELD EMISSION GUN 200 70.0 2.0 450000. GATAN 626 SINGLE TILT LIQUID NITROGEN CRYO TRANSFER HOLDER NITROGEN

STEM mode imaging using Fischione model 3000 HAADF detector. Camera length: 520 mm.

OTHER 2048 2048 1 15 127.0

ADF images collected with a Fischione Model 3000 high-angle annular DF detector

1

Fischione 3000 HAADF

647

Manually selected

2CEI

The initial model was prepared from the human ferritin heavy chain crystal structure from which all heavy atoms were removed. The protein PDB coordinates were converted to structure factors and low pass filtered to 4 nm.

1 O 21.0 FSC 0.143 CUT-OFF RELION 1.4 647 PROJECTION MATCHING RELION 1.4 PROJECTION MATCHING RELION 1.4