wwPDB validation report of PDB entry 6EO1

The initial model was obtained using Modeller (Sali and Blundell, 1993); in particular, the missing fragments were generated for the previously published PDB 4CHV model. This starting model was refined using the Rosetta for cryo-EM package (DiMaio et al., 2015). The symmetry of the channel was restrained during optimization runs (performed following the package tutorial (Wang and DiMaio,2015)). A model with a high fit score to the cryo-EM map and a low energy, as defined by the Rosetta force field, was selected from 100 Rosetta models generated and refined further. Several rounds of manual refinement with Coot (Emsley et al.,2010) and global optimization with Phenix (real_space_refine method (Afonine et al., 2013)) were carried out. Secondary structure constraints were imposed to stabilize the fold of helices and b-sheets during the global optimization.

20 mM KCl, 20 mM Tris-HCl pH 7.6, 1 mM BaCl2, 1 mM EDTA, 0.2 mM cAMP

DM solubilized MloK1 sample was mixed with E. coli polar lipid extract (Avanti Polar Lipids) at a lipid to protein ratio of 0.8 and dialyzed against detergent free buffer. 2D crystals of the lipid embedded protein were obtained within 5 days.

Image processing was done with FOCUS (formerly 2dx), available at FOCUS-EM.org. Arheit et al., 2013a; Arheit et al., 2013b; Arheit et al., 2013c; Gipson et al., 2008; Gipson et al., 2007; Gipson et al., 2011; Biyani et al., 2017. Rsym, Rmerge, and phase errors are not available.

Cyclic nucleotide-modulated potassium channel in the presence of cAMP ligand, reconstituted into 2D lipid membrane crystals.

Gatan Quantum-LS energy filter, with K2 Summit detector

Each image was dose-fractionated in 40 frames (16 sec in total, 0.4-sec frames). The dose rate was set to ~5 counts/sec/physical-pixel (~2.8 e-/s/A2)leading to a total dose of ~45 e-/A2. Pixel size was 1.3A/pix.

Arheit et al., 2013a; Arheit et al., 2013b; Arheit et al., 2013c; Gipson et al., 2008; Gipson et al., 2007; Gipson et al., 2011; Biyani et al., 2017

Cyclic nucleotide-gated potassium channel mll3241

The electron crystallography structure of the cAMP-bound potassium channel MloK1 (PCO-refined)

geometric validation package for ligand chemistry in protein x-ray structures

20191225.v01 (using entries in the PDB archive December 25th 2019)