4h7a
From Proteopedia
Crystal structure of CasB from Thermus thermophilus
Structural highlights
FunctionCSE2_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). Publication Abstract from PubMedThe CRISPR system is an adaptive RNA-based microbial immune system against invasive genetic elements. CasB is an essential protein component in Type I-E Cascade. Here, we characterize CasB proteins from three different organisms as non-specific nucleic acid binding proteins. The Thermobifida fusca CasB crystal structure reveals conserved positive surface charges, which we show are important for its nucleic acid binding function. EM docking reveals that CasB dimerization aligns individual nucleic acid binding surfaces into a curved, elongated binding surface inside Type I-E Cascade, consistent with the putative functions of CasB in ds-DNA recruitment and crRNA-DNA duplex formation steps. STRUCTURED SUMMARY OF PROTEIN INTERACTIONS: TthCasB and TthCasBbind by x-ray crystallography (View interaction) TfuCasB1 and TfuCasB1bind by molecular sieving (View Interaction: 1, 2). Nucleic acid binding surface and dimer interface revealed by CRISPR-associated CasB protein structures.,Nam KH, Huang Q, Ke A FEBS Lett. 2012 Nov 16;586(22):3956-61. doi: 10.1016/j.febslet.2012.09.041. Epub , 2012 Oct 16. PMID:23079036[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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