Evidence map›Paper›PMID 41272318›Full record

ArticleNature chemical biology2026

Molecular basis of SAM-AMP synthesis and degradation in the type III-B CRISPR-Cas system.

Benzhen Duan, Xiaohui Jin, Xiaoman An, Yang Xiao, Qianxi Yang, Hongyu Zhao, Yunxiao Huang, Jingwen Wang, Qian Wang, Fenglei Du and 4 more

Abstract read
PubMed Publisher
In one paragraph

Article in Nature chemical biology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed.

  1. Article
  2. Structural mechanism of SAM-AMP and SAM-AMPNature communications · 2026
    Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

14 authors.

Benzhen Duan *Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Shanghai Fifth People's Hospital, Shanghai Institute of Infectious Disease and Biosecurity, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.ORCID http://orcid.org/0009-0006-1051-3442
Xiaohui Jin *Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Shanghai Fifth People's Hospital, Shanghai Institute of Infectious Disease and Biosecurity, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.ORCID http://orcid.org/0009-0000-2046-2112
Xiaoman AnKey Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Shanghai Fifth People's Hospital, Shanghai Institute of Infectious Disease and Biosecurity, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.
Yang XiaoKey Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Shanghai Fifth People's Hospital, Shanghai Institute of Infectious Disease and Biosecurity, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.
Qianxi YangKey Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Shanghai Fifth People's Hospital, Shanghai Institute of Infectious Disease and Biosecurity, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.ORCID http://orcid.org/0009-0001-0669-4256
Hongyu ZhaoKey Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Shanghai Fifth People's Hospital, Shanghai Institute of Infectious Disease and Biosecurity, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.
Yunxiao HuangKey Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Shanghai Fifth People's Hospital, Shanghai Institute of Infectious Disease and Biosecurity, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.
Jingwen WangKey Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Shanghai Fifth People's Hospital, Shanghai Institute of Infectious Disease and Biosecurity, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.ORCID http://orcid.org/0009-0002-6495-0884
Qian WangKey Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Shanghai Fifth People's Hospital, Shanghai Institute of Infectious Disease and Biosecurity, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.
Fenglei DuKey Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Shanghai Fifth People's Hospital, Shanghai Institute of Infectious Disease and Biosecurity, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.
Lu LuKey Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Shanghai Fifth People's Hospital, Shanghai Institute of Infectious Disease and Biosecurity, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.ORCID http://orcid.org/0000-0002-2255-0391
Lei SunKey Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Shanghai Fifth People's Hospital, Shanghai Institute of Infectious Disease and Biosecurity, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.ORCID http://orcid.org/0000-0001-8741-0202
Zhenguo ChenKey Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Shanghai Fifth People's Hospital, Shanghai Institute of Infectious Disease and Biosecurity, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China. zchen@5thhospital.com.ORCID http://orcid.org/0000-0003-4748-9299
Baoyu ZhaoKey Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microorganisms and Infection, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Shanghai Fifth People's Hospital, Shanghai Institute of Infectious Disease and Biosecurity, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China. baoyuzhao@fudan.edu.cn.ORCID http://orcid.org/0000-0003-4424-1554

Funding

National Natural Science Foundation of China (National Science Foundation of China) 2021hwyq36
6 · The paper itself

Abstract

Upon sensing nonself target RNA, the CorA-associated type III-B CRISPR-Cas system catalyzes S-adenosyl methionine (SAM) and ATP to synthesize SAM-AMP, which activates the effector CorA and triggers immune responses. SAM-AMP can be degraded by NrN and SAM lyase, potentially deactivating the system. Here we find that the type III-B effector complex from Bacteroides fragilis uses a specific mechanism to recognize nonself target RNA and synthesize SAM-AMP. The 3' anti-tag of nonself target RNA induces conformational changes in the Cmr2 subunit, triggering SAM-AMP synthesis independently of the stalk loop of Cmr3 subunit. SAM-AMP binding induces NrN to transit from an open to a closed conformation, enabling hydrolysis of the 3'-5' phosphodiester bond. SAM lyase forms a triangular trimer that specifically degrades SAM-AMP into 5'-methylthioadenosine-AMP and homoserine lactone. These findings unveil unique mechanisms for SAM-AMP synthesis and degradation and provide deeper insights into the molecular basis of type III CRISPR-Cas signaling.

Indexed as

Bacteroides fragilisCRISPR-Cas SystemsS-AdenosylmethionineBacterial ProteinsBacterial ProteinsS-Adenosylmethionine

Identifiers

PMID41272318

What OpenQuestion holds

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.