5FCL

Crystal structure of Cas1 from Pectobacterium atrosepticum

Summary for 5FCL

• Entry DOI: 10.2210/pdb5fcl/pdb
• Descriptor: CRISPR-associated endonuclease Cas1 (2 entities in total)
• Functional Keywords: crispr, cas, adaptation, integrase, structural plasticity, asymmetry, bacteriophages, plasmids, horizontal gene transfer, dna binding protein
• Biological source: Pectobacterium atrosepticum (strain SCRI 1043 / ATCC BAA-672)
• Total number of polymer chains: 6
• Total formula weight: 226221.96

Authors

Wilkinson, M.E.,Nakatani, Y.,Opel-Reading, H.K.,Fineran, P.C.,Krause, K.L. (deposition date: 2015-12-15, release date: 2016-03-16, Last modification date: 2024-03-06)

Primary citation

Wilkinson, M.E.,Nakatani, Y.,Staals, R.H.,Kieper, S.N.,Opel-Reading, H.K.,McKenzie, R.E.,Fineran, P.C.,Krause, K.L.
Structural plasticity and in vivo activity of Cas1 from the type I-F CRISPR-Cas system.
Biochem.J., 473:1063-1072, 2016

PubMed Abstract: CRISPR-Cas systems are adaptive immune systems in prokaryotes that provide protection against viruses and other foreign DNA. In the adaptation stage, foreign DNA is integrated into CRISPR (clustered regularly interspaced short palindromic repeat) arrays as new spacers. These spacers are used in the interference stage to guide effector CRISPR associated (Cas) protein(s) to target complementary foreign invading DNA. Cas1 is the integrase enzyme that is central to the catalysis of spacer integration. There are many diverse types of CRISPR-Cas systems, including type I-F systems, which are typified by a unique Cas1-Cas2-3 adaptation complex. In the present study we characterize the Cas1 protein of the potato phytopathogen Pectobacterium atrosepticum, an important model organism for understanding spacer acquisition in type I-F CRISPR-Cas systems. We demonstrate by mutagenesis that Cas1 is essential for adaptation in vivo and requires a conserved aspartic acid residue. By X-ray crystallography, we show that although P. atrosepticum Cas1 adopts a fold conserved among other Cas1 proteins, it possesses remarkable asymmetry as a result of structural plasticity. In particular, we resolve for the first time a flexible, asymmetric loop that may be unique to type I-F Cas1 proteins, and we discuss the implications of these structural features for DNA binding and enzymatic activity.

PubMed: 26929403
DOI: 10.1042/BCJ20160078

Experimental method

X-RAY DIFFRACTION (2.7 Å)