Ab initio structure of proteinase K from electron-counted MicroED data

Experimental Data Snapshot

  • Resolution: 1.50 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.149 

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This is version 1.2 of the entry. See complete history


Ab initio phasing macromolecular structures using electron-counted MicroED data.

Martynowycz, M.W.Clabbers, M.T.B.Hattne, J.Gonen, T.

(2022) Nat Methods 19: 724-729

  • DOI: https://doi.org/10.1038/s41592-022-01485-4
  • Primary Citation of Related Structures:  
    7SKW, 7SKX

  • PubMed Abstract: 

    Structures of two globular proteins were determined ab initio using microcrystal electron diffraction (MicroED) data that were collected on a direct electron detector in counting mode. Microcrystals were identified using a scanning electron microscope (SEM) and thinned with a focused ion beam (FIB) to produce crystalline lamellae of ideal thickness. Continuous-rotation data were collected using an ultra-low exposure rate to enable electron counting in diffraction. For the first sample, triclinic lysozyme extending to a resolution of 0.87 Å, an ideal helical fragment of only three alanine residues provided initial phases. These phases were improved using density modification, allowing the entire atomic structure to be built automatically. A similar approach was successful on a second macromolecular sample, proteinase K, which is much larger and diffracted to a resolution of 1.5 Å. These results demonstrate that macromolecules can be determined to sub-ångström resolution by MicroED and that ab initio phasing can be successfully applied to counting data.

  • Organizational Affiliation

    Department of Biological Chemistry, University of California, Los Angeles, CA, USA. tgonen@g.ucla.edu.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Proteinase KA [auth C]279Parengyodontium albumMutation(s): 0 
Find proteins for P06873 (Parengyodontium album)
Explore P06873 
Go to UniProtKB:  P06873
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP06873
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

Unit Cell:
Length ( Å )Angle ( ˚ )
a = 67.08α = 90
b = 67.08β = 90
c = 106.78γ = 90
Software Package:
Software NamePurpose
EM Software:
TaskSoftware PackageVersion

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Howard Hughes Medical Institute (HHMI)United States--
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesP41GM136508

Revision History  (Full details and data files)

  • Version 1.0: 2022-06-08
    Type: Initial release
  • Version 1.1: 2022-06-15
    Changes: Database references
  • Version 1.2: 2022-06-22
    Changes: Database references