No gene coding for an adenine deaminase has been described in eukaryotes. However, physiological and genetical evidence indicates that adenine deaminases are present in the ascomycetes. We have cloned and characterised the genes coding for the adenine deaminases of Aspergillus nidulans, Saccharomyces cerevisiae and Schizosaccharomyces pombe. The A.nidulans gene was expressed in Escherichia coli and the purified enzyme shows adenine but not adenosine deaminase activity. The open reading frames coded by the three genes are very similar and obviously related to the bacterial and eukaryotic adenosine deaminases rather than to the bacterial adenine deaminases. The latter are related to allantoinases, ureases and dihydroorotases. The fungal adenine deaminases and the homologous adenosine deaminases differ in a number of residues, some of these being clearly involved in substrate specificity. Other prokaryotic enzymes in the database, while clearly related to the above, do not fit into either sub-class, and may even have a different specificity. These results imply that adenine deaminases have appeared twice in the course of evolution, from different ancestral enzymes constructed both around the alpha/beta barrel scaffold.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.jmb.2003.10.005 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Mitochondrial base editing: from principle, optimization to application.
Cell Biosci
January 2025
Jinshan Hospital Center for Neurosurgery, Jinshan Hospital, Institute for Translational Brain Research, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 201508, China.
In recent years, mitochondrial DNA (mtDNA) base editing systems have emerged as bioengineering tools. DddA-derived cytosine base editors (DdCBEs) have been developed to specifically induce C-to-T conversion in mtDNA by the fusion of sequence-programmable transcription activator-like effector nucleases (TALENs) or zinc-finger nucleases (ZFNs), and split deaminase derived from interbacterial toxins. Similar to DdCBEs, mtDNA adenine base editors have been developed with the ability to introduce targeted A-to-G conversions into human mtDNA.
View Article and Find Full Text PDFPrecise modelling of mitochondrial diseases using optimized mitoBEs.
Nature
January 2025
Changping Laboratory, Beijing, The People's Republic of China.
The development of animal models is crucial for studying and treating mitochondrial diseases. Here we optimized adenine and cytosine deaminases to reduce off-target effects on the transcriptome and the mitochondrial genome, improving the accuracy and efficiency of our newly developed mitochondrial base editors (mitoBEs). Using these upgraded mitoBEs (version 2 (v2)), we targeted 70 mouse mitochondrial DNA mutations analogous to human pathogenic variants, establishing a foundation for mitochondrial disease mouse models.
View Article and Find Full Text PDFGenome-Wide A → G and C → T Mutations Induced by Functional TadA Variants in .
ACS Synth Biol
January 2025
Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P. R. China.
The fusion expression of deoxyribonucleic acid (DNA) replication-related proteins with nucleotide deaminase enzymes promotes random mutations in bacterial genomes, thereby increasing genetic diversity among the population. Most previous studies have focused on cytosine deaminase, which produces only C → T mutations, significantly limiting the variety of mutation types. In this study, we developed a fusion expression system by combining DnaG (RNA primase) with adenine deaminase TadA-8e (DnaG-TadA) in , which is capable of rapidly introducing A → G mutations into the genome, resulting in a 664-fold increase in terms of mutation rate.
View Article and Find Full Text PDFGeneration of inheritable A-to-G transitions using adenine base editing and NG-PAM Cas9 in .
Mol Plant Microbe Interact
November 2024
National University of Singapore , Biological Sciences, 16 Science Drive 4, National Univ. Singapore, Singapore, --, Singapore, 117558;
Towards precise genome editing, base editors have been developed by fusing catalytically compromised Cas9 with deaminase components, mediating C-to-T (cytosine base editors) or A-to-G (adenine base editors) transition. We developed a set of vectors consisting of a 5'-NG-3' PAM-recognising variant of SpCas9 with adenosine deaminases, TadA7.10 or TadA8e.
View Article and Find Full Text PDFDimerization of the deaminase domain and locking interactions with Cas9 boost base editing efficiency in ABE8e.
Nucleic Acids Res
December 2024
Department of Bioengineering, University of California Riverside, 900 University Avenue, 92512 Riverside, CA, USA.
CRISPR-based DNA adenine base editors (ABEs) hold remarkable promises to address human genetic diseases caused by point mutations. ABEs were developed by combining CRISPR-Cas9 with a transfer RNA (tRNA) adenosine deaminase enzyme and through directed evolution, conferring the ability to deaminate DNA. However, the molecular mechanisms driving the efficient DNA deamination in the evolved ABEs remain unresolved.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!