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Argonaute bypasses cellular obstacles without hindrance during target search.

ABSTRACT: Argonaute (Ago) proteins are key players in both gene regulation (eukaryotes) and host defense (prokaryotes). Acting on single-stranded nucleic-acid substrates, Ago relies on base pairing between a small nucleic-acid guide and its complementary target sequences for specificity. To efficiently scan nucleic-acid chains for targets, Ago diffuses laterally along the substrate and must bypass secondary structures as well as protein barriers. Using single-molecule FRET in conjunction with kinetic modelling, we reveal that target scanning is mediated through loose protein-nucleic acid interactions, allowing Ago to slide short distances over secondary structures, as well as to bypass protein barriers via intersegmental transfer. Our combined single-molecule experiment and kinetic modelling approach may serve as a platform to dissect search processes and study the effect of sequence on search kinetics for other nucleic acid-guided proteins.

SUBMITTER: Cui TJ

PROVIDER: S-EPMC6763497 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature

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Argonaute bypasses cellular obstacles without hindrance during target search.

Cui Tao Ju TJ Klein Misha M Hegge Jorrit W JW Chandradoss Stanley D SD van der Oost John J Depken Martin M Joo Chirlmin C

Nature communications 20190926 1

Argonaute (Ago) proteins are key players in both gene regulation (eukaryotes) and host defense (prokaryotes). Acting on single-stranded nucleic-acid substrates, Ago relies on base pairing between a small nucleic-acid guide and its complementary target sequences for specificity. To efficiently scan nucleic-acid chains for targets, Ago diffuses laterally along the substrate and must bypass secondary structures as well as protein barriers. Using single-molecule FRET in conjunction with kinetic mode ...[more]

PMID: 31558728

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