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Structure of a 10-23 Deoxyribozyme Exhibiting a Homodimer Conformation.

ABSTRACT: Deoxyribozymes (DNAzymes) are in vitro evolved DNA sequences capable of catalyzing chemical reactions. The RNA cleaving 10-23 DNAzyme was the first DNAzyme to be evolved and possesses clinical and biotechnical applications as a biosensor and a knockdown agent. DNAzymes do not require the recruitment of other components to cleave RNA and can turnover, thus they have a distinct advantage over other knockdown methods (siRNA, CRISPR, morpholinos). Despite this, a lack of structural and mechanistic information has hindered the optimization and application of the 10-23 DNAzyme. Here, we report a 2.7 Å crystal structure of the RNA cleaving 10-23 DNAzyme in a homodimer conformation. Although proper coordination of the DNAzyme to substrate is observed along with intriguing patterns of bound magnesium ions, the dimer conformation likely does not capture the true catalytic form of the 10-23 DNAzyme.

SUBMITTER: Cramer E

PROVIDER: S-EPMC10312968 | biostudies-literature | 2023 May

REPOSITORIES: biostudies-literature

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Structure of a 10-23 Deoxyribozyme Exhibiting a Homodimer Conformation.

Cramer Evan E Starcovic Sarah S Avey Rebekah R Kaya Ali A Robart Aaron A

Research square 20230531

Deoxyribozymes (DNAzymes) are <i>in vitro</i> evolved DNA sequences capable of catalyzing chemical reactions. The RNA cleaving 10-23 DNAzyme was the first DNAzyme to be evolved and possesses clinical and biotechnical applications as a biosensor and a knockdown agent. DNAzymes do not require the recruitment of other components to cleave RNA and can turnover, thus they have a distinct advantage over other knockdown methods (siRNA, CRISPR, morpholinos). Despite this, a lack of structural and mechan ...[more]

PMID: 37398199

Similar Datasets

Structure of a 10-23 deoxyribozyme exhibiting a homodimer conformation.

Project description:Deoxyribozymes (DNAzymes) are in vitro evolved DNA sequences capable of catalyzing chemical reactions. The RNA-cleaving 10-23 DNAzyme was the first DNAzyme to be evolved and possesses clinical and biotechnical applications as a biosensor and a knockdown agent. DNAzymes do not require the recruitment of other components to cleave RNA and can turnover, thus they have a distinct advantage over other knockdown methods (siRNA, CRISPR, morpholinos). Despite this, a lack of structural and mechanistic information has hindered the optimization and application of the 10-23 DNAzyme. Here, we report a 2.7 Å crystal structure of the RNA-cleaving 10-23 DNAzyme in a homodimer conformation. Although proper coordination of the DNAzyme to substrate is observed along with intriguing patterns of bound magnesium ions, the dimer conformation likely does not capture the true catalytic form of the 10-23 DNAzyme.

| S-EPMC10257704 | biostudies-literature

Single-molecule study of the effects of temperature, pH, and RNA base on the stepwise enzyme kinetics of 10-23 deoxyribozyme.

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| S-EPMC9113834 | biostudies-literature

Structure of the c(10) ring of the yeast mitochondrial ATP synthase in the open conformation.

Project description:The proton pore of the F(1)F(o) ATP synthase consists of a ring of c subunits, which rotates, driven by downhill proton diffusion across the membrane. An essential carboxylate side chain in each subunit provides a proton-binding site. In all the structures of c-rings reported to date, these sites are in a closed, ion-locked state. Structures are here presented of the c(10) ring from Saccharomyces cerevisiae determined at pH 8.3, 6.1 and 5.5, at resolutions of 2.0 Å, 2.5 Å and 2.0 Å, respectively. The overall structure of this mitochondrial c-ring is similar to known homologs, except that the essential carboxylate, Glu59, adopts an open extended conformation. Molecular dynamics simulations reveal that opening of the essential carboxylate is a consequence of the amphiphilic nature of the crystallization buffer. We propose that this new structure represents the functionally open form of the c subunit, which facilitates proton loading and release.

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Structure-function correlations derived from faster variants of a RNA ligase deoxyribozyme.

Project description:We previously reported the in vitro selection of several Mg2+-dependent deoxyribozymes (DNA enzymes) that synthesize a 2'-5' RNA linkage from a 2',3'-cyclic phosphate and a 5'-hydroxyl. Here we subjected the 9A2 deoxyribozyme to re-selection for improved ligation rate. We found two new DNA enzymes (7Z81 and 7Z48) that contain the catalytic core of 7Q10, a previously reported small deoxyribozyme that is unrelated in sequence to 9A2. A third new DNA enzyme (7Z101) is unrelated to either 7Q10 or 9A2. The new 7Z81 and 7Z48 DNA enzymes have ligation rates over an order of magnitude higher than that of 7Q10 itself and they have additional sequence elements that correlate with these faster rates. Our findings provide insight into structure-function relationships of catalytic nucleic acids.

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Identification of the active form of endothelial lipase, a homodimer in a head-to-tail conformation.

Project description:Endothelial lipase (EL) is a member of a subfamily of lipases that act on triglycerides and phospholipids in plasma lipoproteins, which also includes lipoprotein lipase and hepatic lipase. EL has a tropism for high density lipoprotein, and its level of phospholipase activity is similar to its level of triglyceride lipase activity. Inhibition or loss-of-function of EL in mice results in an increase in high density lipoprotein cholesterol, making it a potential therapeutic target. Although hepatic lipase and lipoprotein lipase have been shown to function as homodimers, the active form of EL is not known. In these studies, the size and conformation of the active form of EL were determined. Immunoprecipitation experiments suggested oligomerization. Ultracentrifugation experiments showed that the active form of EL had a molecular weight higher than the molecular weight of a simple monomer but less than a dimer. A construct encoding a covalent head-to-tail homodimer of EL (EL-EL) was expressed and had similar lipolytic activity to EL. The functional molecular weights determined by radiation inactivation were similar for EL and the covalent homodimer EL-EL. We previously showed that EL could be cleaved by proprotein convertases, such as PC5, resulting in loss of activity. In cells overexpressing PC5, the covalent homodimeric EL-EL appeared to be more stable, with reduced cleavage and conserved lipolytic activity. A comparative model obtained using other lipase structures suggests a structure for the head-to-tail EL homodimer that is consistent with the experimental findings. These data confirm the hypothesis that EL is active as a homodimer in head-to-tail conformation.

| S-EPMC2749106 | biostudies-literature

Combining NMR and EPR methods for homodimer protein structure determination.

Project description:There is a general need to develop more powerful and more robust methods for structural characterization of homodimers, homo-oligomers, and multiprotein complexes using solution-state NMR methods. In recent years, there has been increasing emphasis on integrating distinct and complementary methodologies for structure determination of multiprotein complexes. One approach not yet widely used is to obtain intermediate and long-range distance constraints from paramagnetic relaxation enhancements (PRE) and electron paramagnetic resonance (EPR)-based techniques such as double electron electron resonance (DEER), which, when used together, can provide supplemental distance constraints spanning to 10-70 A. In this Communication, we describe integration of PRE and DEER data with conventional solution-state nuclear magnetic resonance (NMR) methods for structure determination of Dsy0195, a homodimer (62 amino acids per monomer) from Desulfitobacterium hafniense. Our results indicate that combination of conventional NMR restraints with only one or a few DEER distance constraints and a small number of PRE constraints is sufficient for the automatic NMR-based structure determination program CYANA to build a network of interchain nuclear Overhauser effect constraints that can be used to accurately define both the homodimer interface and the global homodimer structure. The use of DEER distances as a source of supplemental constraints as described here has virtually no upper molecular weight limit, and utilization of the PRE constraints is limited only by the ability to make accurate assignments of the protein amide proton and nitrogen chemical shifts.

| S-EPMC3057626 | biostudies-literature

Single-round deoxyribozyme discovery.

Project description:Artificial evolution experiments typically use libraries of ∼1015 sequences and require multiple rounds of selection to identify rare variants with a desired activity. Based on the simple structures of some aptamers and nucleic acid enzymes, we hypothesized that functional motifs could be isolated from significantly smaller libraries in a single round of selection followed by high-throughput sequencing. To test this idea, we investigated the catalytic potential of DNA architectures in which twelve or fifteen randomized positions were embedded in a scaffold present in all library members. After incubating in either the presence or absence of lead (which promotes the nonenzymatic cleavage of RNA), library members that cleaved themselves at an RNA linkage were purified by PAGE and characterized by high-throughput sequencing. These selections yielded deoxyribozymes with activities 8- to 30-fold lower than those previously isolated under similar conditions from libraries containing 1014 different sequences, indicating that the disadvantage of using a less diverse pool can be surprisingly small. It was also possible to elucidate the sequence requirements and secondary structures of deoxyribozymes without performing additional experiments. Due to its relative simplicity, we anticipate that this approach will accelerate the discovery of new catalytic DNA and RNA motifs.

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Noncanonical conformation of CDR L1 in the anti-IL-23 antibody CNTO4088.

Project description:CNTO4088 is a monoclonal antibody to human IL-23. The X-ray structure of the Fab fragment revealed an unusual noncanonical conformation of CDR L1. Most antibodies with the kappa light chain exhibit a canonical structure for CDR L1 in which residue 29 anchors the CDR loop to the framework. Analysis of the residues believed to define the conformation of CDR L1 did not explain why it should not adopt a canonical conformation in this antibody. This makes CNTO4088 a benchmark case for developing prediction methods and structure-modeling tools.

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Pseudomonas putida 10-23

Project description:Pseudomonas putida 10-23 Genome sequencing

| PRJNA217833 | ENA

Interleukin (IL)-23 suppresses IL-10 in inflammatory bowel disease.

Project description:Interleukin (IL)-10 plays an important role in immune regulation in the intestine. Immune deregulation is suggested in the pathogenesis of inflammatory bowel disease (IBD). This study aims to elucidate the role of IL-23 in the suppression of IL-10 in the IBD intestinal mucosa. Surgically removed colon specimens were obtained from 16 IBD patients. The expressions of IL-10, IL-23, and IgA in the specimens were examined at the protein and gene transcriptional levels. The gene transcription of IL-10 was assessed by chromatin immunoprecipitation assay and promoter accessibility assay. The levels of IgA and IL-10 were significantly lower, whereas the levels of IL-23 were higher, in IBD specimens than in normal controls. The levels of IgA and IL-10 were negatively correlated with the infiltration of inflammatory cells in the IBD mucosa. The production of IL-10 by lamina propria mononuclear cells was lower in the IBD group than in the control group, and these levels could be enhanced by blocking IL-23. The gene transcription of IL-10 was significantly suppressed in CD4(+) T cells of IBD mucosa; this phenomenon could be replicated in vitro by adding IL-23 in the culture of polarized Th2 cells. Overexpression of IL-23 in the intestinal mucosa suppresses the production of IL-10, which weakens the defensive barrier by reducing the production of IgA in the gut.

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