ausblenden:
Schlagwörter:
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Zusammenfassung:
Adaptive immunity of prokaryotes is mediated by CRISPR-Cas systems that
employ a large variety of Cas protein effectors to identify and destroy
foreign genetic material. The different targeting mechanisms of Cas
proteins rely on the proper protection of the host genome sequence while
allowing for efficient detection of target sequences, termed
protospacers. A short DNA sequence, the protospacer-adjacent motif
(PAM), is frequently used to mark proper target sites. Cas proteins have
evolved a multitude of PAM-interacting domains, which enables them to
cope with viral anti-CRISPR measures that alter the sequence or
accessibility of PAM elements. In this review, we summarize known PAM
recognition strategies for all CRISPR-Cas types. Available structures of
target bound Cas protein effector complexes highlight the diversity of
mechanisms and domain architectures that are employed to guarantee
target specificity.
