A distinct structure of Cas1-Cas2 complex provides insights into the mechanism for the longer spacer acquisition in Pyrococcus furiosus.

In the adaptation stage of CRISPR-Cas systems, the Cas1-Cas2 integrase captures and integrates new invader-derived spacers into the CRISPR locus, serving as a molecular memory of prior infection. As of yet, the structural information of Cas1-Cas2 complex is available only for two species. Here we present the crystal structure of Cas1-Cas2 complex of Pyrococcus furiosus, which showed a distinct architecture from the known Cas1-Cas2 complexes. The shorter C-terminal tail of Pfu Cas2 directs the Cas1 dimers go in the opposite direction, resulting in a different prespacer binding mode. Based on our structural and mutagenesis results, we modeled a prespacer with a shorter duplex and longer 3' overhangs to bind Pfu Cas1-Cas2 complex. The prespacer preference was confirmed by EMSA, fluorescence polarization, and in vitro integration assays. This model provides a potential explanation for the longer spacer acquisition observed in P. furiosus when deleting both cas4 genes. Our study highlights the diversity of the CRISPR adaptation module. Copyright © 2021 Elsevier B.V. All rights reserved.

Citation

Dongmei Tang, Huijuan Li, Chengyong Wu, Tingting Jia, Haihuai He, Shaohua Yao, Yamei Yu, Qiang Chen. A distinct structure of Cas1-Cas2 complex provides insights into the mechanism for the longer spacer acquisition in Pyrococcus furiosus. International journal of biological macromolecules. 2021 Jul 31;183:379-386

Mesh Tags

PMID: 33864868

search → result