Article info Vol. 6  No. 2   pp.  37 ~ 41
Title Purification, crystallization and X-ray crystallographic analysis of Csm1/Csm4 subcomplex in CRISPR/Cas Type III-A system
Authors In-Young Baek1,2, Kwang-Hyun Park2, Woo-chan Ahn2, Yan An2, In-kyu Hwang1* and Euijeon Woo2,3*
Institutions 1Immunology and Immunopharmacology Laboratory, College of Pharmacy, Chungnam National University, Daejeon 34134, Korea 2Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea, 3Department of Structural Biology, KRIBB school of Bioscience, University of Science and Technology, Daejeon 34141, Korea *Correspondence: ejwoo@kribb.re.kr
Abstract The CRISPR/Cas system is an adaptive prokaryotic immune response that defends against exogenous genetic elements. The CRISPR/Cas Type III-A system targets RNA and DNA that is coupled with transcription. The effector complex of the Type III-A CRISPR-Cas system has five Csm components, Csm1~Csm5. The Csm1/Csm4 sub-complex is placed in the crRNA 5' ends of the effector RNP complex and likely involved in the discriminative function for self vs non-self DNA. Here, we prepared Csm1/Csm4 proteins from Thermococcus onnurineus NA1 and crystallized the sub-complex. The Csm1/Csm4 was crystallized using hanging-drop vapor diffusion from a reservoir solution containg 200 mM sodium chloride, 100 mM sodium acetate trihydrate, pH 4.6, 26% (+/-)-2-methyl-2,4-pentanediol. The diffraction data to 2.8 Å resolution show that the crystal belongs to the space group P6522 with unit cell parameters of a=154.91Å, b=154.91Å, c=182.25Å, α=β=90° and γ=120°.