Primed CRISPR adaptation in Escherichia coli cells does not depend on conformational changes in the Cascade effector complex detected in Vitro.

ABSTRACT: In type I CRISPR-Cas systems, primed adaptation of new spacers into CRISPR arrays occurs when the effector Cascade-crRNA complex recognizes imperfectly matched targets that are not subject to efficient CRISPR interference. Thus, primed adaptation allows cells to acquire additional protection against mobile genetic elements that managed to escape interference. Biochemical and biophysical studies suggested that Cascade-crRNA complexes formed on fully matching targets (subject to efficient interference) and on partially mismatched targets that promote primed adaption are structurally different. Here, we probed Escherichia coli Cascade-crRNA complexes bound to matched and mismatched DNA targets using a magnetic tweezers assay. Significant differences in complex stabilities were observed consis

SUBMITTER: Krivoy A 

PROVIDER: S-EPMC5934681 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature