4N06

Crystal structure of Cas1 from Archaeoglobus fulgidus and its nucleolytic activity

Summary for 4N06

• Entry DOI: 10.2210/pdb4n06/pdb
• Descriptor: CRISPR-associated endonuclease Cas1 1 (2 entities in total)
• Functional Keywords: hydrolase
• Biological source: Archaeoglobus fulgidus
• Total number of polymer chains: 2
• Total formula weight: 79101.98

Authors

Kim, T.Y.,Shin, M.,Yen, L.H.T.,Kim, J.S. (deposition date: 2013-10-01, release date: 2014-01-15, Last modification date: 2024-10-09)

Primary citation

Kim, T.Y.,Shin, M.,Yen, L.H.T.,Kim, J.S.
Crystal structure of Cas1 from Archaeoglobus fulgidus and characterization of its nucleolytic activity
Biochem.Biophys.Res.Commun., 441:720-725, 2013

PubMed Abstract: Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) and CRISPR-associated (Cas) proteins are involved in bacterial acquired immunity against incoming hazardous genetic materials. Cas1 is ubiquitous in CRISPR-containing microorganisms and supposed to recognize and cleave a foreign nucleic acid, and integrate the cleaved fragment into host genome using a yet unidentified mechanism. However, all the reported Cas1s did not show the nucleolytic activity, which makes its role still obscure. The elucidated crystal structure of Cas1 from Archaeoglobus fulgidus (AfCas1) shows a butterfly-like dimeric structure. The Asp out of three confirmed nucleolytic residues of Glu, His, and Asp in other Cas1s is replaced with Glu in AfCas1. Further, insertion of five residues into one of two loops, which are close to the catalytic center of and disordered in other Cas1 structures, partially covers the active site of AfCas1. Nonetheless, in vitro assays show that its nucleic acid-binding activity was not impaired against the tested single-stranded (ss) DNA, various forms of double-stranded (ds) DNA, or ssRNA with a hydrolyzing activity against ssRNA and dsDNA in a metal ion-dependent way. These results support the proposed Cas1's function at the early step of this bacterial immune system.

PubMed: 24211577
DOI: 10.1016/j.bbrc.2013.10.122

Experimental method

X-RAY DIFFRACTION (2.4 Å)