4IC1

Crystal structure of SSO0001

Summary for 4IC1

• Entry DOI: 10.2210/pdb4ic1/pdb
• Descriptor: Uncharacterized protein, MANGANESE (II) ION, IRON/SULFUR CLUSTER, ... (4 entities in total)
• Functional Keywords: cas4, crispr, mcsg, exonuclease, psi-biology, structural genomics, unknown function, midwest center for structural genomics
• Biological source: Sulfolobus solfataricus
• Total number of polymer chains: 10
• Total formula weight: 243137.89

Authors

Nocek, B.,Skarina, T.,Lemak, S.,Beloglazova, N.,Flick, R.,Brown, G.,Savchenko, A.,Joachimiak, A.,Yakunin, A.F.,Midwest Center for Structural Genomics (MCSG) (deposition date: 2012-12-09, release date: 2013-01-16, Last modification date: 2024-10-30)

Primary citation

Lemak, S.,Beloglazova, N.,Nocek, B.,Skarina, T.,Flick, R.,Brown, G.,Popovic, A.,Joachimiak, A.,Savchenko, A.,Yakunin, A.F.
Toroidal structure and DNA cleavage by the CRISPR-associated [4Fe-4S] cluster containing Cas4 nuclease SSO0001 from Sulfolobus solfataricus.
J.Am.Chem.Soc., 135:17476-17487, 2013

PubMed Abstract: Cas4 proteins, a core protein family associated with the microbial system of adaptive immunity CRISPR, are predicted to function in the adaptation step of the CRISPR mechanism. Here we show that the Cas4 protein SSO0001 from the archaeon Sulfolobus solfataricus has metal-dependent endonuclease and 5'→3' exonuclease activities against single-stranded DNA, as well as ATP-independent DNA unwinding activity toward double-stranded DNA. The crystal structure of SSO0001 revealed a decameric toroid formed by five dimers with each protomer containing one [4Fe-4S] cluster and one Mn(2+) ion bound in the active site located inside the internal tunnel. The conserved RecB motif and four Cys residues are important for DNA binding and cleavage activities, whereas DNA unwinding depends on several residues located near the [4Fe-4S] cluster. Our results suggest that Cas4 proteins might contribute to the addition of novel CRISPR spacers through the formation of 3'-DNA overhangs and to the degradation of foreign DNA.

PubMed: 24171432
DOI: 10.1021/ja408729b

Experimental method

X-RAY DIFFRACTION (2.35 Å)