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Updated: Jan 6, 2026

CD Spectroscopy to Study DNA-Protein Interactions
Published on: February 10, 2022
cGAS and CD-NTase enzymes: structure, mechanism, and evolution.
1Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Parker Institute for Cancer Immunotherapy at Dana-Farber Cancer Institute, Boston, MA 02115, USA.
Cyclic GMP-AMP synthase (cGAS) and its homologs form a widespread enzyme family (CD-NTase) that synthesizes diverse RNA signals. These enzymes, found across biology, are crucial for cellular responses to environmental changes.
Area of Science:
- Biochemistry
- Molecular Biology
- Immunology
Background:
- Cyclic GMP-AMP synthase (cGAS) is a key enzyme in human cells for detecting cytosolic DNA and initiating immune responses.
- Discoveries of cGAS homologs in various organisms reveal ancient and widespread cGAS-like signaling pathways.
- The cGAS/DncV-like nucleotidyltransferase (CD-NTase) family synthesizes diverse noncanonical RNA signals, including cyclic dinucleotides and trinucleotides.
Purpose of the Study:
- To explore the evolutionary history and functional diversity of the cGAS/DncV-like nucleotidyltransferase (CD-NTase) enzyme family.
- To understand the structural and biochemical basis of CD-NTase signaling in cellular responses.
- To identify novel human CD-NTase family members and their potential functions beyond innate immunity.
Main Methods:
- Comparative genomics and structural biology to identify and characterize cGAS homologs.
- Biochemical assays to determine the enzymatic activities and synthesized products of CD-NTase enzymes.
- Bioinformatic analysis to explore the evolutionary relationships and functional implications of CD-NTase family members.
Main Results:
- The cGAS/DncV-like nucleotidyltransferase (CD-NTase) family is ancient and widespread, encompassing diverse enzymes from bacteria to humans.
- Structural and biochemical studies elucidated the mechanism of CD-NTase enzymes in synthesizing various cyclic and linear RNA oligonucleotides.
- Uncharacterized human genes, such as MB21D2 and Mab21L1, were identified as members of the CD-NTase family, suggesting roles beyond immunity.
Conclusions:
- CD-NTase enzymes represent a conserved signaling system across biology, crucial for cellular adaptation to environmental cues.
- Understanding CD-NTase structure-function relationships provides insights into diverse cellular signaling pathways.
- The identification of novel human CD-NTase family members opens new avenues for research into their roles in health and disease.
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