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- Title
- DESIGN, CONSTRUCTION, AND CHARACTERIZATION OF THE YSGR MINIMAL CODON FAB LIBRARY FOR CHAPERONE-ASSISTED RNA CRYSTALLOGRAPHY.
- Creator
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Holmes, Sean, Ye, Jingdong, University of Central Florida
- Abstract / Description
-
Of the entire human genome, 90% of all genetic information is transcribed but only a fraction of that subsequent RNA is translated into proteins. RNAs which are not translated into proteins are deemed non-coding RNAs. Little is known about this large category of noncoding RNAs, although they perform a variety of functions within the cell. RNA crystallography is used to study RNA tertiary structure, which gives insight to the function of these non-coding RNAs. However, complications associated...
Show moreOf the entire human genome, 90% of all genetic information is transcribed but only a fraction of that subsequent RNA is translated into proteins. RNAs which are not translated into proteins are deemed non-coding RNAs. Little is known about this large category of noncoding RNAs, although they perform a variety of functions within the cell. RNA crystallography is used to study RNA tertiary structure, which gives insight to the function of these non-coding RNAs. However, complications associated with RNA crystallography arise due to RNA's lack of surface functional group diversity, flexible tertiary structure, and conformational heterogeneity. A novel technique, Chaperone-assisted RNA crystallography (CARC), can greatly improve the success in crystallization of RNA. With this technique, synthetic antibodies called Antigen Binding Fragments (Fabs) are employed as crystallization chaperones to promote the structure elucidation of certain target RNAs. To identify Fabs that complex with RNA molecules of interest, we constructed a randomized library of synthetic antibodies enriched in ligand binding regions with tyrosine, serine, glycine, and arginine residues. This Fab protein library was constructed with a minimal codon design, and then screened against a variety of RNA targets. Several Fabs have been identified and isolated through phage display selection against three RNA targets. These Fabs were expressed and biochemically characterized for their binding affinities and specificities. To date, five Fabs have been identified and they have outstanding capabilities in binding their specific RNA antigen.
Show less - Date Issued
- 2012
- Identifier
- CFH0004167, ucf:44856
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004167
- Title
- Preparation, Characterization, and Delivery of Antibodies Binding to a Model Oncogenic RNA, Human Initiator tRNA.
- Creator
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Archer, Jennifer, Santra, Swadeshmukul, Ye, Jingdong, Ye, Jingdong, Self, William, Khaled, Annette, University of Central Florida
- Abstract / Description
-
Non-coding RNAs (ncRNAs) account for a higher percent of the genome than coding mRNAs, and are implicated in human disease such as cancer, neurological, cardiac and many others. While the majority of ncRNAs involved in disease were originally attributed to a class of RNAs called micro RNAs (miRNAs) with a small size of only about 19 -24 base pairs, emerging research has now demonstrated a class of long non-coding RNAs (lncRNAs) that have a size of over 200 base pairs to be responsible for...
Show moreNon-coding RNAs (ncRNAs) account for a higher percent of the genome than coding mRNAs, and are implicated in human disease such as cancer, neurological, cardiac and many others. While the majority of ncRNAs involved in disease were originally attributed to a class of RNAs called micro RNAs (miRNAs) with a small size of only about 19 -24 base pairs, emerging research has now demonstrated a class of long non-coding RNAs (lncRNAs) that have a size of over 200 base pairs to be responsible for gene regulation and other functional roles and have also found to contribute to pathogenesis in humans. The increased size and structural complexity require novel tools to study their interactions beyond RNA interference. Synthetic antibodies are classic tools and therapeutics utilized to study and treat proteins involved in human disease. Likewise we hypothesize that structured RNAs can also take advantage of synthetic antibodies to probe their functions and be utilized as therapeutics.Currently, antibodies have been raised against microbial riboswitches and other structured RNAs of single-celled organisms, and only one human structured RNA to the best of our knowledge. However, no one has yet to create a synthetic antibody capable of behaving as a therapeutic against a structured RNA. We therefore sought to raise an antibody Fab against a structured RNA, human initiator tRNA, a model oncogenic non-coding RNA and demonstrate its efficacy in vitro. We then characterized the antibody and explored delivery options in cancer cells including the use of nanoparticle delivery systems. With the emerging transcriptome revealing new ncRNAs implicated in human disease, our research has begun to address a new therapeutic strategy, laying down the foundation for the future of structured RNA-targeted therapies.
Show less - Date Issued
- 2014
- Identifier
- CFE0005756, ucf:50072
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005756
- Title
- SURFACE ENTROPY REDUCTION TO INCREASE THE CRYSTALLIZABILITY OF THE FAB-RNA COMPLEX.
- Creator
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P.Ravindran, Priyadarshini, Ye, Jingdong, University of Central Florida
- Abstract / Description
-
Crystallizing RNA has been an imperative facet and a challenging task in the world of RNA research. Assistive methods such as Chaperone Assisted RNA Crystallography (CARC), employing monoclonal antibody fragments (Fabs) as crystallization chaperones have enabled us to obtain RNA crystal structures by increasing the crystal contacts and providing initial phasing information. Using this technology the crystal structure of ΔC209 P4-P6 RNA (an independent folding domain of the self-splicing...
Show moreCrystallizing RNA has been an imperative facet and a challenging task in the world of RNA research. Assistive methods such as Chaperone Assisted RNA Crystallography (CARC), employing monoclonal antibody fragments (Fabs) as crystallization chaperones have enabled us to obtain RNA crystal structures by increasing the crystal contacts and providing initial phasing information. Using this technology the crystal structure of ΔC209 P4-P6 RNA (an independent folding domain of the self-splicing Tetrahymena group I intron) complexed to Fab2 (high affinity binding Fab) has been resolved to 1.95 Å. Although the complexed class I ligase ribozyme has also been crystallized using CARC, in practice, it has been found that the crystallization of, large RNA-Fab complex remains a confrontation. The possible reason for this difficulty is that Fabs have not been optimized for crystallization when complexed with RNA. Here we have used the Surface Entropy Reduction technique (SER) for the optimization process. Candidate residues for mutations were identified based on combining results from visual inspection of ΔC209 P4-P6/Fab2 crystal structure complex using pyMOL software and a web- based SER software. The protruding lysine and glutamate residues were mutated to a set of alanine (Super Mutant Alanine SMA) and serine (Super Mutant Serine SMS) mutant clones. Filter binding assay studies confirmed that the mutant clones bind to ΔC209 P4-P6 with similar binding affinities as that of the parent Fab2. Large scale expression of the mutants, parent clone and ΔC209 P4-P6 RNA were optimised. Crystal trays for ΔC209 P4-P6 complexed with Fab2, Fab2SMA and Fab2SMS were set-up side-by-side using Hampton crystal screen kits and ~600 conditions including temperature as a variable condition were screened. Crystal screening shows significantly higher crystal-forming ratios for the mutant complexes. As the chosen SER residues are far away from the CDR regions of the Fab, the same set of mutations can be potentially applied to other Fabs binding to a variety of ribozymes and riboswitches to improve the crystallizability of the Fab-RNA complex.
Show less - Date Issued
- 2011
- Identifier
- CFE0003944, ucf:48711
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003944
- Title
- Structural and Functional Studies of Glycine Riboswitches and Development of Fab Chaperone Assisted RNA Crystallography.
- Creator
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Sherman, Eileen, Ye, Jingdong, Kolpashchikov, Dmitry, Koculi, Eda, Harper, James, Self, William, University of Central Florida
- Abstract / Description
-
The glycine riboswitch is a structured RNA found upstream of genes in mRNA transcripts in many bacteria, functioning as a biofeedback gene regulator. Upon binding glycine, a complete RNA transcript including gene sequences is transcribed, effectively turning on gene expression. In an effort to understand the intricacies of its functioning, many mutants of the riboswitch were made and characterized during Ph. D. work, resulting in discovery of a P0 duplex/kink-turn motif involving a few...
Show moreThe glycine riboswitch is a structured RNA found upstream of genes in mRNA transcripts in many bacteria, functioning as a biofeedback gene regulator. Upon binding glycine, a complete RNA transcript including gene sequences is transcribed, effectively turning on gene expression. In an effort to understand the intricacies of its functioning, many mutants of the riboswitch were made and characterized during Ph. D. work, resulting in discovery of a P0 duplex/kink-turn motif involving a few nucleotides upstream of the established glycine riboswitch sequence which changed its ligand binding characteristics (Chapter 1). Previously, the two aptamers of the riboswitch were thought to cooperatively bind glycine, but with the inclusion of this leader sequence which forms a kink turn motif with the linker between the two aptamers, glycine binding in one aptamer no longer requires glycine binding in the other. Furthermore, the Kd from three species tested are now a similar, lower value of about 5 (&)#181;M, indicating authenticity of this new consensus sequence. Glycine binding and interaptamer interaction both enhanced one another in trans aptamer assays. Another discovery from this was a shortened construct including all of aptamer II but only part of aptamer I in which a few specific nucleotides prevented glycine binding in aptamer II (Chapter 2). This may provide insight into the nature of interaptamer interactions in the full switch; addition of an oligonucleotide complimentary to these nucleotides restored glycine binding ability to aptamer II. With future development, this could also be a useful molecular biology tool, using two signals, glycine and an oligonucleotide, to allow gene expression.To precisely understand how any macromolecule functions, a 3D structure, obtainable by x-ray crystallography, is vital. A new technique to accomplish that for RNA, precedented in the protein world, is Fab chaperoned crystallography, which has advantages compared to RNA alone. A phage displayed library of Fabs with reduced codon diversity designed for RNA was created, the YSGR Min library (Chapter 3). Its Fabs had specificities and affinities equal to or greater than previous libraries which were originally created for phage displayed selection against proteins. Fab chaperoned RNA crystallography is currently in progress for the glycine riboswitch; the best resolution thus far is 5.3 (&)#197; (Chapter 4). In addition to providing molecular insight into its gene regulation mechanism, a structure of the glycine riboswitch could be applied for use in structure based drug design of novel antibiotics targeting the riboswitch to disrupt important downstream carbon cycle genes in pathogenic bacteria.
Show less - Date Issued
- 2014
- Identifier
- CFE0005549, ucf:50285
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005549
