3S5U

Crystal structure of CRISPR associated protein

3S5U の概要

• エントリーDOI: 10.2210/pdb3s5u/pdb
• 分子名称: Putative uncharacterized protein, CALCIUM ION (3 entities in total)
• 機能のキーワード: crispr, crispr adaptation mechanism, new spacer aquisition, dsdna binding, dna binding protein
• 由来する生物種: Enterococcus faecalis
• タンパク質・核酸の鎖数: 8
• 化学式量合計: 204786.84

構造登録者

Ke, A.,Nam, K.H. (登録日: 2011-05-23, 公開日: 2011-06-22, 最終更新日: 2024-02-28)

主引用文献

Nam, K.H.,Kurinov, I.,Ke, A.
Crystal structure of clustered regularly interspaced short palindromic repeats (CRISPR)-associated Csn2 protein revealed Ca2+-dependent double-stranded DNA binding activity.
J. Biol. Chem., 286:30759-30768, 2011

PubMed Abstract: Clustered regularly interspaced short palindromic repeats (CRISPR) and their associated protein genes (cas genes) are widespread in bacteria and archaea. They form a line of RNA-based immunity to eradicate invading bacteriophages and malicious plasmids. A key molecular event during this process is the acquisition of new spacers into the CRISPR loci to guide the selective degradation of the matching foreign genetic elements. Csn2 is a Nmeni subtype-specific cas gene required for new spacer acquisition. Here we characterize the Enterococcus faecalis Csn2 protein as a double-stranded (ds-) DNA-binding protein and report its 2.7 Å tetrameric ring structure. The inner circle of the Csn2 tetrameric ring is ∼26 Å wide and populated with conserved lysine residues poised for nonspecific interactions with ds-DNA. Each Csn2 protomer contains an α/β domain and an α-helical domain; significant hinge motion was observed between these two domains. Ca(2+) was located at strategic positions in the oligomerization interface. We further showed that removal of Ca(2+) ions altered the oligomerization state of Csn2, which in turn severely decreased its affinity for ds-DNA. In summary, our results provided the first insight into the function of the Csn2 protein in CRISPR adaptation by revealing that it is a ds-DNA-binding protein functioning at the quaternary structure level and regulated by Ca(2+) ions.

PubMed: 21697083
DOI: 10.1074/jbc.M111.256263

実験手法

X-RAY DIFFRACTION (2.7 Å)