7T2S

Structure of E. coli upec-117 Cap18 3'-5' exonuclease

Summary for 7T2S

• Entry DOI: 10.2210/pdb7t2s/pdb
• Descriptor: 3'-5' exonuclease, ACETATE ION (3 entities in total)
• Functional Keywords: cbass, dna binding protein
• Biological source: Escherichia coli
• Total number of polymer chains: 1
• Total formula weight: 21277.20

Authors

Liang, Q.,Richey, S.T.,Ye, Q.,Lau, R.K.,Corbett, K.D. (deposition date: 2021-12-06, release date: 2022-07-20, Last modification date: 2024-02-28)

Primary citation

Liang, Q.,Richey, S.T.,Ur, S.N.,Ye, Q.,Lau, R.K.,Corbett, K.D.
Structure and activity of a bacterial defense-associated 3'-5' exonuclease.
Protein Sci., 31:e4374-e4374, 2022

PubMed Abstract: The widespread CBASS (cyclic oligonucleotide-based anti-phage signaling system) immune systems in bacteria protect their hosts from bacteriophage infection by triggering programmed cell death. CBASS systems all encode a cyclic oligonucleotide synthase related to eukaryotic cGAS but use diverse regulators and effector proteins including nucleases, phospholipases, and membrane-disrupting proteins to effect cell death. Cap18 is a predicted 3'-5' exonuclease associated with hundreds of CBASS systems, whose structure, biochemical activities, and biological roles remain unknown. Here we show that Cap18 is a DEDDh-family exonuclease related to the bacterial exonucleases RNase T and Orn and has nonspecific 3'-5' DNA exonuclease activity. Cap18 is commonly found in CBASS systems with associated CapW or CapH+CapP transcription factors, suggesting that it may coordinate with these proteins to regulate CBASS transcription in response to DNA damage. These data expand the repertoire of enzymatic activities associated with bacterial CBASS systems and provide new insights into the regulation of these important bacterial immune systems.

PubMed: 35762727
DOI: 10.1002/pro.4374

Experimental method

X-RAY DIFFRACTION (1.82 Å)