6d06
From Proteopedia
Human ADAR2d E488Y mutant complexed with dsRNA containing an abasic site opposite the edited base
Structural highlights
Function[RED1_HUMAN] Catalyzes the hydrolytic deamination of adenosine to inosine in double-stranded RNA (dsRNA) referred to as A-to-I RNA editing. This may affect gene expression and function in a number of ways that include mRNA translation by changing codons and hence the amino acid sequence of proteins; pre-mRNA splicing by altering splice site recognition sequences; RNA stability by changing sequences involved in nuclease recognition; genetic stability in the case of RNA virus genomes by changing sequences during viral RNA replication; and RNA structure-dependent activities such as microRNA production or targeting or protein-RNA interactions. Can edit both viral and cellular RNAs and can edit RNAs at multiple sites (hyper-editing) or at specific sites (site-specific editing). Its cellular RNA substrates include: bladder cancer-associated protein (BLCAP), neurotransmitter receptors for glutamate (GRIA2 and GRIK2) and serotonin (HTR2C), GABA receptor (GABRA3) and potassium voltage-gated channel (KCNA1). Site-specific RNA editing of transcripts encoding these proteins results in amino acid substitutions which consequently alter their functional activities. Edits GRIA2 at both the Q/R and R/G sites efficiently but converts the adenosine in hotspot1 much less efficiently. Can exert a proviral effect towards human immunodeficiency virus type 1 (HIV-1) and enhances its replication via both an editing-dependent and editing-independent mechanism. The former involves editing of adenosines in the 5'UTR while the latter occurs via suppression of EIF2AK2/PKR activation and function. Can inhibit cell proliferation and migration and can stimulate exocytosis.[1] [2] [3] Publication Abstract from PubMedMolecules capable of directing changes to nucleic acid sequences are powerful tools for molecular biology and promising candidates for the therapeutic correction of disease-causing mutations. However, unwanted reactions at off-target sites complicate their use. Here we report selective combinations of mutant editing enzyme and directing oligonucleotide. Mutations in human ADAR2 (adenosine deaminase acting on RNA 2) that introduce aromatic amino acids at position 488 reduce background RNA editing. This residue is juxtaposed to the nucleobase that pairs with the editing site adenine, suggesting a steric clash for the bulky mutants. Replacing this nucleobase with a hydrogen atom removes the clash and restores editing activity. A crystal structure of the E488Y mutant bound to abasic site-containing RNA shows the accommodation of the tyrosine side chain. Finally, we demonstrate directed RNA editing in vitro and in human cells using mutant ADAR2 proteins and modified guide RNAs with reduced off-target activity. A Bump-Hole Approach for Directed RNA Editing.,Monteleone LR, Matthews MM, Palumbo CM, Thomas JM, Zheng Y, Chiang Y, Fisher AJ, Beal PA Cell Chem Biol. 2018 Nov 23. pii: S2451-9456(18)30385-4. doi:, 10.1016/j.chembiol.2018.10.025. PMID:30581135[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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