2I8E

Structure of SSO1404, a predicted DNA repair-associated protein from Sulfolobus solfataricus P2

Summary for 2I8E

• Entry DOI: 10.2210/pdb2i8e/pdb
• Descriptor: Hypothetical protein, IODIDE ION (3 entities in total)
• Functional Keywords: dna repair, unknown function, structural genomics, midwest center for structural genomics, mcsg, psi, protein structure initiative
• Biological source: Sulfolobus solfataricus
• Total number of polymer chains: 1
• Total formula weight: 12601.08

Authors

Wang, S.,Zimmerman, M.D.,Kudritska, M.,Chruszcz, M.,Savchenko, A.,Edwards, A.,Joachimiak, A.,Minor, W.,Midwest Center for Structural Genomics (MCSG) (deposition date: 2006-09-01, release date: 2006-09-26, Last modification date: 2024-11-20)

Primary citation

Beloglazova, N.,Brown, G.,Zimmerman, M.D.,Proudfoot, M.,Makarova, K.S.,Kudritska, M.,Kochinyan, S.,Wang, S.,Chruszcz, M.,Minor, W.,Koonin, E.V.,Edwards, A.M.,Savchenko, A.,Yakunin, A.F.
A novel family of sequence-specific endoribonucleases associated with the clustered regularly interspaced short palindromic repeats.
J.Biol.Chem., 283:20361-20371, 2008

PubMed Abstract: Clustered regularly interspaced short palindromic repeats (CRISPRs) together with the associated CAS proteins protect microbial cells from invasion by foreign genetic elements using presently unknown molecular mechanisms. All CRISPR systems contain proteins of the CAS2 family, suggesting that these uncharacterized proteins play a central role in this process. Here we show that the CAS2 proteins represent a novel family of endoribonucleases. Six purified CAS2 proteins from diverse organisms cleaved single-stranded RNAs preferentially within U-rich regions. A representative CAS2 enzyme, SSO1404 from Sulfolobus solfataricus, cleaved the phosphodiester linkage on the 3'-side and generated 5'-phosphate- and 3'-hydroxyl-terminated oligonucleotides. The crystal structure of SSO1404 was solved at 1.6A resolution revealing the first ribonuclease with a ferredoxin-like fold. Mutagenesis of SSO1404 identified six residues (Tyr-9, Asp-10, Arg-17, Arg-19, Arg-31, and Phe-37) that are important for enzymatic activity and suggested that Asp-10 might be the principal catalytic residue. Thus, CAS2 proteins are sequence-specific endoribonucleases, and we propose that their role in the CRISPR-mediated anti-phage defense might involve degradation of phage or cellular mRNAs.

PubMed: 18482976
DOI: 10.1074/jbc.M803225200

Experimental method

X-RAY DIFFRACTION (1.59 Å)