7KFT

Partial Cas6-RT-Cas1--Cas2 complex

Summary for 7KFT

• Entry DOI: 10.2210/pdb7kft/pdb
• Related: 7KFU
• EMDB information: 22855 22856
• Descriptor: Cas2, Cas6-RT-Cas1 (2 entities in total)
• Functional Keywords: complex, hydrolase, crispr cas protein, reverse transcriptase
• Biological source: Thiomicrospira sp.; More
• Total number of polymer chains: 5
• Total formula weight: 361774.77

Authors

Hoel, C.M.,Wang, J.Y.,Doudna, J.A.,Brohawn, S.G. (deposition date: 2020-10-14, release date: 2021-03-31, Last modification date: 2024-03-06)

Primary citation

Wang, J.Y.,Hoel, C.M.,Al-Shayeb, B.,Banfield, J.F.,Brohawn, S.G.,Doudna, J.A.
Structural coordination between active sites of a CRISPR reverse transcriptase-integrase complex.
Nat Commun, 12:2571-2571, 2021

PubMed 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.

PubMed: 33958590
DOI: 10.1038/s41467-021-22900-y

Experimental method

ELECTRON MICROSCOPY (3.4 Å)