4ej3

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Crystal structure of a CRISPR associated protein from Thermus thermophilus HB8

Structural highlights

4ej3 is a 2 chain structure with sequence from Thermus thermophilus HB8. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.52Å
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

CSE1_THET8 CRISPR (clustered regularly interspaced short palindromic repeat), is an adaptive immune system that provides protection against mobile genetic elements (viruses, transposable elements and conjugative plasmids). CRISPR clusters contain sequences complementary to antecedent mobile elements and target invading nucleic acids. CRISPR clusters are transcribed and processed into CRISPR RNA (crRNA) (By similarity). A component of Cascade, which participates in CRISPR interference, the third stage of CRISPR immunity. Cascade binds both crRNA and in a sequence-specific manner negatively supercoiled dsDNA target. This leads to the formation of an R-loop in which the crRNA binds the target DNA, displacing the noncomplementary strand. Cas3 is recruited to Cascade, probably via interactions with CasA, nicks target DNA and then unwinds and cleaves the target, leading to DNA degradation and invader neutralization. CasA is not required for formation of Cascade, but probably enhances binding to and subsequent recognition of both target dsDNA and ssDNA (By similarity).

See Also

Contents


PDB ID 4ej3

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OCA

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