7c0i
From Proteopedia
Crystal structure of chimeric mutant of E3L in complex with Z-DNA
Structural highlights
DiseaseDSRAD_HUMAN Defects in ADAR are a cause of dyschromatosis symmetrical hereditaria (DSH) [MIM:127400; also known as reticulate acropigmentation of Dohi. DSH is a pigmentary genodermatosis of autosomal dominant inheritance characterized by a mixture of hyperpigmented and hypopigmented macules distributed on the dorsal parts of the hands and feet.[1] [2] [3] FunctionDSRAD_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 serotonin (HTR2C) and GABA receptor (GABRA3). Site-specific RNA editing of transcripts encoding these proteins results in amino acid substitutions which consequently alters their functional activities. Exhibits low-level editing at the GRIA2 Q/R site, but edits efficiently at the R/G site and HOTSPOT1. Its viral RNA substrates include: hepatitis C virus (HCV), vesicular stomatitis virus (VSV), measles virus (MV), hepatitis delta virus (HDV), and human immunodeficiency virus type 1 (HIV-1). Exhibits either a proviral (HDV, MV, VSV and HIV-1) or an antiviral effect (HCV) and this can be editing-dependent (HDV and HCV), editing-independent (VSV and MV) or both (HIV-1). Impairs HCV replication via RNA editing at multiple sites. Enhances the replication of MV, VSV and HIV-1 through an editing-independent mechanism via suppression of EIF2AK2/PKR activation and function. Stimulates both the release and infectivity of HIV-1 viral particles by an editing-dependent mechanism where it associates with viral RNAs and edits adenosines in the 5'UTR and the Rev and Tat coding sequence. Can enhance viral replication of HDV via A-to-I editing at a site designated as amber/W, thereby changing an UAG amber stop codon to an UIG tryptophan (W) codon that permits synthesis of the large delta antigen (L-HDAg) which has a key role in the assembly of viral particles. However, high levels of ADAR1 inhibit HDV replication.[4] [5] [6] [7] [8] [9] [10] [11] [12] [13] E3_VACCW Publication Abstract from PubMedLeft-handed Z-DNA is radically different from the most common right-handed B-DNA and can be stabilized by interactions with the Zalpha domain, which is found in a group of proteins, such as human ADAR1 and viral E3L proteins. It is well-known that most Zalpha domains bind to Z-DNA in a conformation-specific manner and induce rapid B-Z transition in physiological conditions. Although many structural and biochemical studies have identified the detailed interactions between the Zalpha domain and Z-DNA, little is known about the molecular basis of the B-Z transition process. In this study, we successfully converted the B-Z transition-defective Zalpha domain, vvZalphaE3L, into a B-Z converter by improving B-DNA binding ability, suggesting that B-DNA binding is involved in the B-Z transition. In addition, we engineered the canonical B-DNA binding protein GH5 into a Zalpha-like protein having both Z-DNA binding and B-Z transition activities by introducing Z-DNA interacting residues. Crystal structures of these mutants of vvZalphaE3L and GH5 complexed with Z-DNA confirmed the significance of conserved Z-DNA binding interactions. Altogether, our results provide molecular insight into how Zalpha domains obtain unusual conformational specificity and induce the B-Z transition. Dual conformational recognition by Z-DNA binding protein is important for the B-Z transition process.,Park C, Zheng X, Park CY, Kim J, Lee SK, Won H, Choi J, Kim YG, Choi HJ Nucleic Acids Res. 2020 Dec 16;48(22):12957-12971. doi: 10.1093/nar/gkaa1115. PMID:33245772[14] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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