Structural coordination between active sites of a CRISPR reverse transcriptase-integrase complex

Joy Y. Wang, Christopher M. Hoel, Basem Al-Shayeb, Jillian F. Banfield, Stephen G. Brohawn, Jennifer A. Doudna

Research output: Contribution to journalArticleResearchpeer-review

11 Citations (Scopus)

Abstract

CRISPR-Cas systems provide adaptive immunity in bacteria and archaea, beginning with integration of foreign sequences into the host CRISPR genomic locus and followed by transcription and maturation of CRISPR RNAs (crRNAs). In some CRISPR systems, a reverse transcriptase (RT) fusion to the Cas1 integrase and Cas6 maturase creates a single protein that enables concerted sequence integration and crRNA production. To elucidate how the RT-integrase organizes distinct enzymatic activities, we present the cryo-EM structure of a Cas6-RT-Cas1—Cas2 CRISPR integrase complex. The structure reveals a heterohexamer in which the RT directly contacts the integrase and maturase domains, suggesting functional coordination between all three active sites. Together with biochemical experiments, our data support a model of sequential enzymatic activities that enable CRISPR sequence acquisition from RNA and DNA substrates. These findings highlight an expanded capacity of some CRISPR systems to acquire diverse sequences that direct CRISPR-mediated interference.

Original languageEnglish
Article number2571
Number of pages14
JournalNature Communications
Volume12
Issue number1
DOIs
Publication statusPublished - 6 May 2021
Externally publishedYes

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