title: Crystallization and preliminary X-ray diffraction analysis of the Cmr2-Cmr3 subcomplex in the CRISPR-Cas RNA-silencing effector complex.
abstract: Clustered, regularly interspaced, short palindromic repeat (CRISPR) loci, found in prokaryotes, are transcribed to produce CRISPR RNAs (crRNAs). The Cmr proteins (Cmr1-6) and crRNA form a ribonucleoprotein complex that degrades target RNAs derived from invading genetic elements. Cmr2dHD, a Cmr2 variant lacking the N-terminal putative HD nuclease domain, and Cmr3 were co-expressed in Escherichia coli cells and co-purified as a complex. The Cmr2dHD-Cmr3 complex was co-crystallized with 3'-AMP by the vapour-diffusion method. The crystals diffracted to 2.6 Å resolution using synchrotron radiation at the Photon Factory. The crystals belonged to the orthorhombic space group I222, with unit-cell parameters a = 103.9, b = 136.7, c = 192.0 Å. The asymmetric unit of the crystals is expected to contain one Cmr2dHD-Cmr3 complex with a Matthews coefficient of 3.0 Å(3) Da(-1) and a solvent content of 59%.
authors.affiliation: Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba-shi, Ibaraki 305-8566, Japan.
authors.forename: Takuo
authors.initials: T
authors.lastname: Osawa
authors.forename: Hideko
authors.initials: H
authors.lastname: Inanaga
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Numata
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D003460:Crystallization; D014644:Genetic Variation; D011387:Prokaryotic Cells / Q000502:physiology; D034622:RNA Interference / Q000502:physiology; D014961:X-Ray Diffraction
chemical_list: D001426:Bacterial Proteins
keywords: CRISPR; Cas; Cmr2; Cmr3; RNA silencing