 |
PDBsum entry 6dd5
|
|
|
|
References listed in PDB file
|
 |
|
Key reference
|
|
|
Title
|
|
A reverse transcriptase-Cas1 fusion protein contains a cas6 domain required for both crispr RNA biogenesis and RNA spacer acquisition.
|
|
|
Authors
|
|
G.Mohr,
S.Silas,
J.L.Stamos,
K.S.Makarova,
L.M.Markham,
J.Yao,
P.Lucas-Elío,
A.Sanchez-Amat,
A.Z.Fire,
E.V.Koonin,
A.M.Lambowitz.
|
|
|
Ref.
|
|
Mol Cell, 2018,
72,
700.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
Prokaryotic CRISPR-Cas systems provide adaptive immunity by integrating portions
of foreign nucleic acids (spacers) into genomic CRISPR arrays. Cas6 proteins
then process CRISPR array transcripts into spacer-derived RNAs (CRISPR RNAs;
crRNAs) that target Cas nucleases to matching invaders. We find that a
Marinomonas mediterranea fusion protein combines three enzymatic domains (Cas6,
reverse transcriptase [RT], and Cas1), which function in both crRNA biogenesis
and spacer acquisition from RNA and DNA. We report a crystal structure of this
divergent Cas6, identify amino acids required for Cas6 activity, show that the
Cas6 domain is required for RT activity and RNA spacer acquisition, and
demonstrate that CRISPR-repeat binding to Cas6 regulates RT activity.
Co-evolution of putative interacting surfaces suggests a specific structural
interaction between the Cas6 and RT domains, and phylogenetic analysis reveals
repeated, stable association of free-standing Cas6s with CRISPR RTs in multiple
microbial lineages, indicating that a functional interaction between these
proteins preceded evolution of the fusion.
|
|
|
|
|
|
|
