DNA Targeting by a Minimal CRISPR RNA-Guided Cascade
| Autor: | David W. Taylor, Eva Nogales, Jack E. Kornfeld, Jennifer A. Doudna, Megan L. Hochstrasser |
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| Rok vydání: | 2016 |
| Předmět: |
Models
Molecular Protein Conformation alpha-Helical 0301 basic medicine Amino Acid Motifs Gene Expression Computational biology Biology Article Substrate Specificity 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Protein structure Bacterial Proteins Genome editing Operon Escherichia coli CRISPR Protein Interaction Domains and Motifs Desulfovibrio vulgaris Cloning Molecular Molecular Biology Gene Editing Genetics Trans-activating crRNA Binding Sites Cas9 Cryoelectron Microscopy RNA DNA Cell Biology Endonucleases Recombinant Proteins Kinetics RNA Bacterial 030104 developmental biology chemistry Nucleic acid Nucleic Acid Conformation CRISPR-Cas Systems 030217 neurology & neurosurgery Protein Binding RNA Guide Kinetoplastida |
| Zdroj: | Molecular Cell. 63:840-851 |
| ISSN: | 1097-2765 |
| Popis: | Bacteria employ surveillance complexes guided by CRISPR (clustered, regularly interspaced, short palindromic repeats) RNAs (crRNAs) to target foreign nucleic acids for destruction. Although most type I and type III CRISPR systems require four or more distinct proteins to form multi-subunit surveillance complexes, the type I-C systems use just three proteins to achieve crRNA maturation and double-stranded DNA target recognition. We show that each protein plays multiple functional and structural roles: Cas5c cleaves pre-crRNAs and recruits Cas7 to position the RNA guide for DNA binding and unwinding by Cas8c. Cryoelectron microscopy reconstructions of free and DNA-bound forms of the Cascade/I-C surveillance complex reveal conformational changes that enable R-loop formation with distinct positioning of each DNA strand. This streamlined type I-C system explains how CRISPR pathways can evolve compact structures that retain full functionality as RNA-guided DNA capture platforms. |
| Databáze: | OpenAIRE |
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