Honors & Awards
Bioneer poster presentation award (2nd place) in 2011 KOLIS annual meeting, KOLIS (Korean Life Scientists in the bay area) (2011)
A scholarship for good achievement in Department of Molecular Biology, Dankook University (1st semester in 1999)
A scholarship for good achievement in Department of Molecular Biology, Dankook University (2nd Semester in 1997)
Doctor of Philosophy, Korea University (2009)
Master of Science, Dankook University, Department of Molecular Biology (2002)
Bachelor of Science, Dankook University, Department of Molecular Biology (2000)
Jianghong Rao, Postdoctoral Faculty Sponsor
Efficient Method for Site-Specific F-18-Labeling of Biomolecules Using the Rapid Condensation Reaction between 2-Cyanobenzothiazole and Cysteine
2012; 23 (9): 1902-1908
An efficient method based on a rapid condensation reaction between 2-cyanobenzothiazole (CBT) and cysteine has been developed for (18)F-labeling of N-terminal cysteine-bearing peptides and proteins. An (18)F-labeled dimeric cRGD ([(18)F]CBTRGD(2)) has been synthesized with an excellent radiochemical yield (92% based on radio-HPLC conversion, 80% decay-corrected, and isolated yield) and radiochemical purity (>99%) under mild conditions using (18)F-CBT, and shown good in vivo tumor targeting efficiency for PET imaging. The labeling strategy was also applied to the site-specific (18)F-labeling of a protein, Renilla lucifierase (RLuc8) with a cysteine residue at its N-terminus. The protein labeling was achieved with 12% of decay-corrected radiochemical yield and more than 99% radiochemical purity. This strategy should provide a general approach for efficient and site-specific (18)F-labeling of various peptides and proteins for in vivo molecular imaging applications.
View details for DOI 10.1021/bc300273m
View details for Web of Science ID 000308833600021
View details for PubMedID 22845703
A strategy to enhance the binding affinity of fluorophore-aptamer pairs for RNA tagging with neomycin conjugation
2012; 48 (80): 10034-10036
Fluorogenic sulforhodamine-neomycin conjugates have been designed and synthesized for RNA tagging. Conjugates were fluorescently activated by binding to RNA aptamers and exhibited greater than 250-400 fold enhancement in binding affinity relative to corresponding unconjugated fluorophores.
View details for DOI 10.1039/c2cc34498j
View details for Web of Science ID 000308653800025
View details for PubMedID 22951899
An RNA Aptamer That Selectively Recognizes Symmetric Dimethylation of Arginine 8 in the Histone H3 N-Terminal Peptide
NUCLEIC ACID THERAPEUTICS
2011; 21 (3): 157-163
Epigenetic modifications of N-terminal histone tails, especially histone H3, are important for the regulation of the target genes in chromatin. Specific methods for detection of these modifications in histone H3?N-terminal peptides are valuable tools for diagnostic and therapeutic purposes. As an alternative to antibodies, RNA aptamers display compatible binding affinities and selectivites against various biologically relevant targets. Systematic evolution of ligands by exponential enrichment (SELEX) was performed against histone H3R8Me2sym. A 14-amino acid peptide that mimics this modified histone tail was prepared in a biotinylated form and 10 selection cycles of SELEX were carried out. This produced 4 aptamers, one of which (clone 1) was observed to have low nanomolar binding affinity (K(d)=12 nM) against the cognate peptide. The affinity of this aptamer is comparable to 2 commercially available antibodies against differently modified histone H3 peptides and it displays a greater selectivity than the antibodies.
View details for DOI 10.1089/nat.2011.0300
View details for Web of Science ID 000293654100006
View details for PubMedID 21749292
Methylation-mediated control of aurora kinase B and Haspin with epigenetically modified histone H3 N-terminal peptides
BIOORGANIC & MEDICINAL CHEMISTRY
2011; 19 (7): 2373-2377
If multiple post-translational modifications are responsible for important biological markers, additional specificity must be present to serve as embedded combinatorial markers for phosphorylation. In this investigation, we have attempted to elucidate the specificity of AURKB and Haspin by using peptides of various lengths that contain all possible methylations, acetylations, and phosphorylations in histone H3 N-terminal peptides. The activity of AURKB is affected by a wide range of modifications from R2 to K14, while that of Haspin is affected significantly by modifications at R2 and K4. In cases where kinase activity is reduced substantially by other modifications, dimethylation at R2 and R8 totally abolishes phosphorylation at S10 promoted by AURKB and as does dimethylation at R2 on Haspin promoted phosphorylation at T3.
View details for DOI 10.1016/j.bmc.2011.02.011
View details for Web of Science ID 000288792400028
View details for PubMedID 21397507
Combining SELEX Screening and Rational Design to Develop Light-Up Fluorophore-RNA Aptamer Pairs for RNA Tagging
ACS CHEMICAL BIOLOGY
2010; 5 (11): 1065-1074
We report here a new small molecule fluorogen and RNA aptamer pair for RNA labeling. The small-molecule fluorogen is designed on the basis of fluorescently quenched sulforhodamine dye. The SELEX (Systematic Evolution of Ligands by EXponential enrichment) procedure and fluorescence screening in E. coli have been applied to discover the aptamer that can specifically activate the fluorogen with micromolar binding affinity. The systematic mutation and truncation study on the aptamer structure determined the minimum binding domain of the aptamer. A series of rationally modified fluorogen analogues have been made to probe the interacting groups of fluorogen with the aptamer. These results led to the design of a much improved fluorogen ASR 7 that displayed a 33-fold increase in the binding affinity for the selected aptamer in comparison to the original ASR 1 and an 88-fold increase in the fluorescence emission after the aptamer binding. This study demonstrates the value of combining in vitro SELEX and E. coli fluorescence screening with rational modifications in discovering and optimizing new fluorogen-RNA aptamer labeling pairs.
View details for DOI 10.1021/cb1001894
View details for Web of Science ID 000284437800009
View details for PubMedID 20809562
Histone H3 N-Terminal Peptide Binds Directly to Its Own mRNA: A Possible Mode of Feedback Inhibition to Control Translation
2009; 10 (8): 1313-1316
Give me some feedback: In vitro selection of aptamers against the H3 peptide provided specific hairpin RNAs that possess high homology with histone H3 mRNA. The identified H3 hairpin RNA binds specifically to the H3 peptide with micromolar affinity and dose-dependently inhibits in vitro translation of the H3 protein. Consequently, the hairpin RNA and H3 peptide are one of the rare cis- and trans-elements on coding regions found among housekeeping proteins in higher eukaryotes.
View details for DOI 10.1002/cbic.200900154
View details for Web of Science ID 000266561500008
View details for PubMedID 19405068
An RNA aptamer that recognizes a specific conformation of the protein calsenilin
BIOORGANIC & MEDICINAL CHEMISTRY
2007; 15 (24): 7545-7552
The generation of molecules that selectively recognize specific conformations of a protein is an important component of the elucidation protein function. We have used SELEX (Systematic Evolution of Ligands by EXponential enrichment) technology to produce aptamers that bind in a conformationally selective manner to calsenilin, which involved in Ca(2+)-mediated apoptotic signaling. Since the conformations of calsenilin are quite different in the presence and absence of Ca(2+), aptamers were selected against the dimeric protein both under calcium-bound and calcium-free conditions. We have found that aptamer-12 selectively binds to the dimeric form of the protein in the presence of calcium ion, while the binding of aptamer-2 does not discriminate between the Ca(2+) bound and unbound protein. Data obtained from biochemical and biophysical experiments suggest that a dominant conformation of calcium-bound calsenilin exists in one dominant conformation and that one aptamer can be generated to recognize this conformation. In addition, observation made in this effort that aptamers selected against the two different conformations of calsenilin have different characteristics suggest that aptamers can serve as a plausible tool for recognizing various conformations of proteins, even those caused by interactions with small molecules or ions such as Ca(2+).
View details for DOI 10.1016/j.bmc.2007.09.013
View details for Web of Science ID 000253489200004
View details for PubMedID 17904852
- alpha-helical peptide containing N,N-dimethyl lysine residues displays low-nanomolar and highly specific binding to RRE RNA JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 2007; 129 (15): 4514-?
A strategy for the design of selective RNA binding agents. Preparation and RRE RNA binding affinities of a neomycin-peptide nucleic acid heteroconjugate library
BIOORGANIC & MEDICINAL CHEMISTRY LETTERS
2006; 16 (18): 4757-4759
We have successfully developed a new strategy for RNA ligand design, which applies the antisense concept to enhance and make more specific loop region interactions while at the same time preserving stem region anchoring. The heteroconjugates, prepared in this effort, have proven to be the most specific small molecule ligands against RRE RNA that have been uncovered to date.
View details for DOI 10.1016/j.bmcl.2006.06.094
View details for Web of Science ID 000240395300009
View details for PubMedID 16875816
A hybrid molecule that prohibits amyloid fibrils and alleviates neuronal toxicity induced by beta-amyloid (1-42)
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
2005; 328 (4): 816-823
Inhibition of oligomeric amyloid beta (Abeta) peptide or fibril formation has emerged as a major therapeutic target for developing new drugs for Alzheimer's disease. We focused on developing inhibitors by synthesizing hybrid molecules of ferulic acid and styryl benzene, which has been known as a fibril binder. Initially, cell-based assay was carried out to evaluate the effective compound. A selected effector, 1, alleviated the Abeta-induced neuronal toxicity in differentiated SH-SY5Y human neuroblastoma cells. The effector could also inhibit Abeta fibril formation, monitored by thioflavin T fluorescence intensity assay and transmitted electron microscopic images. A strong binding affinity of 1 to non-fibrous monomer-like Abeta, which was immobilized to a surface chip, was measured using a surface plasmon resonance technique. The data suggest that the effector shifts the equilibrium of multimeric Abeta, inhibiting the pathogenic oligomer or fibril formation.
View details for DOI 10.1016/j.bbrc.2005.01.030
View details for Web of Science ID 000227233000002
View details for PubMedID 15707952
An approach to enhance specificity against RNA targets using heteroconjugates of aminoglycosides and chloramphenicol (or linezolid)
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
2004; 126 (7): 1956-1957
We describe the design and synthesis of new heterodimeric conjugates, which are comprised of a neomycin B (Neo) stem-binding component and a chloramphenicol (Cam) or linezolid (Lnz) loop-binding component. Some of the heterodimeric conjugates display enhanced affinities to RNA targets and that binding occurs in both stem and loop regions of the RNA. In addition, the results of foot-printing and mutation studies suggest that the enhanced binding affinity of the conjugates is RNA sequence-specific.
View details for DOI 10.1021/ja038937y
View details for Web of Science ID 000189096200017
View details for PubMedID 14971927
Mimicry of tandem repeat peptides against cell surface carbohydrates
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
2002; 124 (47): 13996-13997
Our approach to multivalent peptide construction relies on tentacle peptides, also known as a multiple antigenic peptides, which contain two and four repeats of a selected peptide. In this communication, we report the results of preliminary studies aimed at (1) the selection of short peptides against the carbohydrate, sLeX, (2) the synthesis of tentacle dimers and tetramers of the selected peptides, and (3) the determination of affinities and specificities of the peptides to several related carbohydrates by using the surface plasmon resonance (SPR) and the equilibrium dialysis techniques. Binding affinity studies, as well as assays of in vitro binding of the peptides to a sLeX-specific cell line, have shown that the tetrameric peptides bind to the cell surface sugars.
View details for DOI 10.1021/ja026937c
View details for Web of Science ID 000179404200018
View details for PubMedID 12440889