We apologize for Proteopedia being slow to respond. For the past two years, a new implementation of Proteopedia has been being built. Soon, it will replace this 18-year old system. All existing content will be moved to the new system at a date that will be announced here.

4k9b

From Proteopedia

Jump to: navigation, search

Structure of Ternary Complex of cGAS with dsDNA and Bound c[G(2 ,5 )pA(3 ,5 )p]

Structural highlights

4k9b is a 3 chain structure with sequence from Mus musculus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.26Å
Ligands:	, , ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

CGAS_MOUSE Nucleotidyltransferase that catalyzes formation of cyclic GMP-AMP (cGAMP) from ATP and GTP and exhibits antiviral activity. Has antiviral activity by acting as a key cytosolic DNA sensor, the presence of DNA in the cytoplasm being a danger signal that triggers the immune responses. Binds cytosolic DNA directly, leading to activation and synthesis of cGAMP, a second messenger that binds to and activates TMEM173/STING, thereby triggering type-I interferon production.

Publication Abstract from PubMed

Recent studies identified cyclic GMP-AMP (cGAMP) as a metazoan second messenger triggering an interferon response. cGAMP is generated from GTP and ATP by cytoplasmic dsDNA sensor cGAMP synthase (cGAS). We combined structural, chemical, biochemical, and cellular assays to demonstrate that this second messenger contains G(2',5')pA and A(3',5')pG phosphodiester linkages, designated c[G(2',5')pA(3',5')p]. We show that, upon dsDNA binding, cGAS is activated through conformational transitions, resulting in formation of a catalytically competent and accessible nucleotide-binding pocket for generation of c[G(2',5')pA(3',5')p]. We demonstrate that cyclization occurs in a stepwise manner through initial generation of 5'-pppG(2',5')pA prior to cyclization to c[G(2',5')pA(3',5')p], with the latter positioned precisely in the catalytic pocket. Mutants of cGAS dsDNA-binding or catalytic pocket residues exhibit reduced or abrogated activity. Our studies have identified c[G(2',5')pA(3',5')p] as a founding member of a family of metazoan 2',5'-containing cyclic heterodinucleotide second messengers distinct from bacterial 3',5' cyclic dinucleotides.

Cyclic [G(2',5')pA(3',5')p] is the metazoan second messenger produced by DNA-activated cyclic GMP-AMP synthase.,Gao P, Ascano M, Wu Y, Barchet W, Gaffney BL, Zillinger T, Serganov AA, Liu Y, Jones RA, Hartmann G, Tuschl T, Patel DJ Cell. 2013 May 23;153(5):1094-107. doi: 10.1016/j.cell.2013.04.046. Epub 2013 May, 3. PMID:23647843^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Gao P, Ascano M, Wu Y, Barchet W, Gaffney BL, Zillinger T, Serganov AA, Liu Y, Jones RA, Hartmann G, Tuschl T, Patel DJ. Cyclic [G(2',5')pA(3',5')p] is the metazoan second messenger produced by DNA-activated cyclic GMP-AMP synthase. Cell. 2013 May 23;153(5):1094-107. doi: 10.1016/j.cell.2013.04.046. Epub 2013 May, 3. PMID:23647843 doi:10.1016/j.cell.2013.04.046