2.2 å resolution cryo-EM structure of β-galactosidase in complex with a cell-permeant inhibitor

Alberto Bartesaghi, Alan Merk, Soojay Banerjee, Doreen Matthies, Xiongwu Wu, Jacqueline L S Milne, Sriram Subramaniam

Research output: Contribution to journalArticle

Abstract

Cryo-electron microscopy (cryo-EM) is rapidly emerging as a powerful tool for protein structure determination at high resolution. Here we report the structure of a complex between Escherichia coli b-galactosidase and the cell-permeant inhibitor phenylethyl b-D-thiogalactopyranoside (PETG), determined by cryo-EM at an average resolution of ∼2.2 angstroms (å). Besides the PETG ligand, we identified densities in the map for ∼800 water molecules and for magnesium and sodium ions. Although it is likely that continued advances in detector technology may further enhance resolution, our findings demonstrate that preparation of specimens of adequate quality and intrinsic protein flexibility, rather than imaging or image-processing technologies, now represent the major bottlenecks to routinely achieving resolutions close to 2 å using single-particle cryo-EM.

Original languageEnglish (US)
Pages (from-to)1147-1151
Number of pages5
JournalScience
Volume348
Issue number6239
DOIs
StatePublished - Jun 5 2015
Externally publishedYes

ASJC Scopus subject areas

  • General
  • Medicine(all)

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