A5056651625- CRISPR and Genetic Engineering
- Viral Infections and Immunology Research
- RNA and protein synthesis mechanisms
- Bacterial Genetics and Biotechnology
- DNA Repair Mechanisms
- Plant Virus Research Studies
- Cytomegalovirus and herpesvirus research
- RNA Interference and Gene Delivery
- Evolution and Genetic Dynamics
- Bacteriophages and microbial interactions
- Advanced biosensing and bioanalysis techniques
- Electron Spin Resonance Studies
- RNA modifications and cancer
- Genomics and Chromatin Dynamics
- RNA regulation and disease
- Plasmonic and Surface Plasmon Research
- Photosynthetic Processes and Mechanisms
- Mosquito-borne diseases and control
- Regional Development and Policy
- Parasitic Infections and Diagnostics
- Spectroscopy and Quantum Chemical Studies
- Carcinogens and Genotoxicity Assessment
- Innovation and Socioeconomic Development
- Magnetism in coordination complexes
- Lanthanide and Transition Metal Complexes
Institut Pasteur
2024-2025
Université Paris Cité
2024
Centre National de la Recherche Scientifique
2024
University of Bonn
2021-2022
Center of Advanced European Studies and Research
2021
University Hospital Bonn
2021
University of St Andrews
2010-2020
Sensory Cloud (United States)
2020
Leipzig University
2016-2018
University of Iceland
2012
The Clustered Regularly Interspaced Palindromic Repeats (CRISPR) system is an adaptive immune in prokaryotes. Interference complexes encoded by CRISPR-associated (cas) genes utilize small RNAs for homology-directed detection and subsequent degradation of invading genetic elements, they have been classified into three main types (I–III). Type III share the Cas10 subunit but are subclassifed as type IIIA (CSM) IIIB (CMR), depending on their specificity DNA or RNA targets, respectively. role...
The CRISPR system for prokaryotic adaptive immunity provides RNA-mediated protection from viruses and mobile genetic elements. When viral RNA transcripts are detected, type III systems adopt an activated state that licenses DNA interference synthesis of cyclic oligoadenylate (cOA). cOA activates nucleases transcription factors orchestrate the antiviral response. We demonstrate is subject to tight temporal control, commencing on target binding, deactivated rapidly as cleaved dissociates....
Cyclic oligoadenylate (cOA) secondary messengers are generated by type III CRISPR systems in response to viral infection. cOA allosterically activates the ancillary ribonucleases Csx1/Csm6, which degrade RNA non-specifically using a HEPN (Higher Eukaryotes and Prokaryotes, Nucleotide binding) active site. This provides effective immunity but can also lead growth arrest infected cells, necessitating means deactivate ribonuclease once infection has been cleared. In crenarchaea, dedicated ring...
Viruses compete with each other for limited cellular resources, and some viruses deliver defense mechanisms that protect the host from competing genetic parasites. PARIS is a system, often encoded in viral genomes, composed of 53 kDa ABC ATPase (AriA) 35 TOPRIM nuclease (AriB). Here we show AriA AriB assemble into 425 supramolecular immune complex. We use cryo-EM to determine structure this complex which explains how six molecules propeller-shaped scaffold coordinates three subunits AriB....
Viruses compete with each other for limited cellular resources, and some deliver defence mechanisms that protect the host from competing genetic parasites
The CRISPR–Cas system for prokaryotic adaptive immunity provides RNA-mediated protection from viruses and mobile genetic elements. Adaptation is dependent on the Cas1 Cas2 proteins along with varying accessory proteins. Here we analyse process in Sulfolobus solfataricus, showing that while catalyze spacer integration vitro, host factors are required specificity. Specific also requires at least 400 bp of leader sequence, presence hydrolysable ATP, suggestive an active may involve DNA...
Cyclic nucleotide second messengers are increasingly implicated in prokaryotic anti-viral defence systems. Type III CRISPR systems synthesise cyclic oligoadenylate (cOA) upon detecting foreign RNA, activating ancillary nucleases that can be toxic to cells, necessitating mechanisms remove cOA operate via immunity rather than abortive infection. Previously, we demonstrated the Sulfolobus solfataricus type III-D complex generates tetra-adenylate (cA4), ribonuclease Csx1, and showed subsequent...
The function of proteins is linked to their conformations that can be resolved with several high-resolution methods. However, only a few methods provide the temporal order intermediates and conformational changes, each having its limitations. Here, we combine pulsed electron–electron double resonance spectroscopy microsecond freeze-hyperquenching setup achieve spatiotemporal resolution in angstrom range lower time scale. We show change Cα-helix cyclic nucleotide-binding domain Mesorhizobium...
Transfer RNA molecules have been recently recognized as widespread targets of bacterial immune systems. Translation inhibition through tRNA cleavage or modification inhibits phage propagation, thereby protecting the population. To counteract this, some viruses encode their own molecules, allowing infection to take place. The AriB effector PARIS defence system is a Toprim nuclease previously shown target E. coli tRNALys(UUU), but not tRNALys(UUU) variant encoded by bacteriophage T5. We...
Xeroderma pigmentosum factor D (XPD) is a 5′–3′ superfamily 2 helicase and the founding member of family DNA helicases with iron–sulphur cluster domains. As component transcription II H (TFIIH), XPD involved in unwinding during nucleotide excision repair (NER). Archaeal closely related sequence to eukaryal enzyme crystal structure archaeal has provided molecular understanding mutations causing xeroderma trichothiodystrophy humans. Consistent role NER, we show that can initiate from bubble...
Within the field of DNA nanotechnology, numerous methods were developed to produce complex two- and three-dimensional nanostructures for many different emerging applications. These structures typically suffer from a low tolerance against non-optimal environmental conditions including elevated temperatures. Here, we apply chemical ligation method covalently seal nicks between adjacent 5' phosphorylated 3' amine-modified strands within nanostructures. Using cost-effective enzymatic strand...
XPB helicase is an integral part of transcription factor TFIIH, required for both initiation and nucleotide excision repair (NER). Along with the XPD helicase, plays a crucial but only partly understood role in defining extending DNA bubble around lesions NER. Archaea encode clear homologues XPD, structural studies these proteins have yielded key insights relevant to eukaryal system. Here we show that archaeal functions structure-specific nuclease, Bax1, as helicase-nuclease machine unwinds...
Site-directed spin labeling and pulsed electron–electron double resonance (PELDOR or DEER) have previously been applied successfully to study the structure dynamics of nucleic acids. Spin acids at specific sites requires covalent attachment labels, which involves rather complicated laborious chemical synthesis. Here, we use a noncovalent label strategy that bypasses chemistry show binding specificity efficiency are large enough enable PELDOR DEER measurements in DNA duplexes duplex bound Lac...
In type I CRISPR-Cas systems, primed adaptation of new spacers into CRISPR arrays occurs when the effector Cascade-crRNA complex recognizes imperfectly matched targets that are not subject to efficient interference. Thus, allows cells acquire additional protection against mobile genetic elements managed escape Biochemical and biophysical studies suggested complexes formed on fully matching (subject interference) partially mismatched promote adaption structurally different. Here, we probed...
DinG (damage inducible gene G) is a bacterial superfamily 2 helicase with 5′→3′ polarity. related to the XPD (xeroderma pigmentosum complementation group D) family, and they have in common an FeS (iron–sulfur)-binding domain that essential for activity. In bacilli clostridia, has become fused N-terminal predicted be exonuclease. present paper we show protein from Staphylococcus aureus lacks not DNA helicase, although it retains DNA-dependent ATP hydrolysis Instead, enzyme active 3′→5′...
Summary CRISPR antiviral defense systems such as the well-known DNA-targeting Cas9- and more complex RNA-targeting type III are widespread in bacteria archea 1, 2 . The can orchestrate a response that is initiated by synthesis of cyclic oligoadenylates (cOAs) upon foreign RNA recognition 3–5 These second messenger molecules bind to CARF (CRISPR associated Rossmann-fold) domains dedicated effector proteins often DNAses, RNAses, or putative transcription factors 6 activated effectors interfere...
Abstract Prokaryotic CRISPR-Cas immune systems detect and cleave foreign nucleic acids. In type III systems, the Cas10 subunit of activated recognition complex synthesizes cyclic oligoadenylates (cOAs), second messengers that activate downstream ancillary effector proteins. Once viral attack has been weathered, elimination extant cOA is essential to limit antiviral response allow cellular recovery. Various families ring nucleases have identified, specializing in degradation cOAs either as...