PT  - JOURNAL ARTICLE
AU  - Grzegorz Chojnowski
AU  - Adam J. Simpkin
AU  - Diego A. Leonardo
AU  - Wolfram Seifert-Davila
AU  - Dan E. Vivas-Ruiz
AU  - Ronan M. Keegan
AU  - Daniel J. Rigden
TI  - Identification of unknown proteins in X-ray crystallography and cryo-EM
AID  - 10.1101/2021.04.18.440303
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.04.18.440303
4099  - http://biorxiv.org/content/early/2021/04/18/2021.04.18.440303.short
4100  - http://biorxiv.org/content/early/2021/04/18/2021.04.18.440303.full
AB  - Although experimental protein structure determination usually targets known proteins, chains of unknown sequence are often encountered. They can be purified from natural sources, appear as an unexpected fragment of a well characterized protein or as a contaminant. Regardless of the source of the problem, the unknown protein always requires tedious characterization. Here we present an automated pipeline for the identification of protein sequences from cryo-EM reconstructions and crystallographic data. We present the method’s application to characterize the crystal structure of an unknown protein purified from a snake venom. We also show that the approach can be successfully applied to the identification of protein sequences and validation of sequence assignments in cryo-EM protein structures.Competing Interest StatementThe authors have declared no competing interest.