Associate
Hyo-Joong Kim

Education

BS in Chemistry Education. Seoul National University, South Korea (1991)
MS in Chemistry. Seoul National University, South Korea (1993)
PhD in Chemistry. University of Alabama, Tuscaloosa, AL (2004)
Postdoctoral Research Associate. University of Georgia, Athens, GA (2004-2006)

Research summary

Darwinian Chemistry. RNA is thought to be the only genetic material on early Earth until DNA emerged. I am trying to get an RNA molecule that catalyzes the template-directed synthesis of RNA.

Dynamic Combinatorial Chemistry. Detection of specific nucleic acid sequence in complex genomic mixture is an important area. For this goal, I am using two oligonucleotide primers which can bind reversibly each other at the end of their sequence. These segmented primers are expected to prime in the presence of the target sequence without mismatch problem.

Recent Publications

A Direct Prebiotic Synthesis of Nicotinamide Nucleotide
Hyo-Joong Kim, Steven A. Benner
Chemistry , Wiley-VCH (2018) Jan 12;24(3):581-584. doi: 10.1002/chem.201705394
<Abstract>

Under the "RNA World" hypothesis, an early episode of natural history on Earth used RNA as the only genetically encoded molecule to catalyze steps in its metabolism catalysis. This, according to the hypothesis, included RNA catalysts that used RNA cofactors. However, the RNA World hypothesis places special demands on prebiotic chemistry, which must now deliver not only four ribonucleosides, but also must deliver the "functional" portion of these RNA cofactors. While some (e.g. methionine) present no particular challenges, nicotinamide ribose is special. Essential to its role in biological oxidations and reductions, its glycosidic bond that holds a positively charged heterocycle is especially unstable with respect to cleavage. Nevertheless, we are able to report here a prebiotic synthesis of phosphorylated nicotinamide ribose under conditions that also conveniently lead to the adenosine phosphate components of this and other RNA cofactors.

Prebiotic stereoselective synthesis of purine and noncanonical pyrimidine nucleotide from nucleobases and phosphorylated carbohydrates
Hyo-Joong Kim, Steven A. Benner
Proc. Natl. Acad. Sci. USA (2017) October, 114 (43) 11315-11320. https://doi.org/10.1073/pnas.1710778114
<Abstract>

According to a current "RNA first" model for the origin of life, RNA emerged in some form on early Earth to become the first biopolymer to support Darwinism here. Threose nucleic acid (TNA) and other polyelectrolytes are also considered as the possible first Darwinian biopolymer(s). This model is being developed by research pursuing a "Discontinuous Synthesis Model" (DSM) for the formation of RNA and/or TNA from precursor molecules that might have been available on early Earth from prebiotic reactions, with the goal of making the model less discontinuous. In general, this is done by examining the reactivity of isolated products from proposed steps that generate those products, with increasing complexity of the reaction mixtures in the proposed mineralogical environments. Here, we report that adenine, diaminopurine, and hypoxanthine nucleoside phosphates and a noncanonical pyrimidine nucleoside (zebularine) phosphate can be formed from the direct coupling reaction of cyclic carbohydrate phosphates with the free nucleobases. The reaction is stereoselective, giving only the β-anomer of the nucleotides within detectable limits. For purines, the coupling is also regioselective, giving the N-9 nucleotide for adenine as a major product. In the DSM, phosphorylated carbohydrates are presumed to have been available via reactions explored previously [Krishnamurthy R, Guntha S, Eschenmoser A (2000) Angew Chem Int Ed 39:2281-2285], while nucleobases are presumed to have been available from hydrogen cyanide and other nitrogenous species formed in Earth's primitive atmosphere.

Assays To Detect the Formation of Triphosphates of Unnatural Nucleotides: Application to Escherichia coli Nucleoside Diphosphate Kinase
Mariko F. Matsuura, Ryan W. Shaw, Jennifer D. Moses, Hyo-Joong Kim, Myong-Jung Kim, Myong-Sang Kim, Shuichi Hoshika, Nilesh Karalkar, and Steven A. Benner
ACS Synthetic Biology , American Chemical Society (2016) 5 (3), pp 234-240 DOI: 10.1021/acssynbio.5b00172
<Abstract>

One frontier in synthetic biology seeks to move artificially expanded genetic information systems (AEGIS) into natural living cells and to arrange the metabolism of those cells to allow them to replicate plasmids built from these unnatural genetic systems. In addition to requiring polymerases that replicate AEGIS oligonucleotides, such cells require metabolic pathways that biosynthesize the triphosphates of AEGIS nucleosides, the substrates for those polymerases. Such pathways generally require nucleoside and nucleotide kinases to phosphorylate AEGIS nucleosides and nucleotides on the path to these triphosphates. Thus, constructing such pathways focuses on engineering natural nucleoside and nucleotide kinases, which often do not accept the unnatural AEGIS biosynthetic intermediates. This, in turn, requires assays that allow the enzyme engineer to follow the kinase reaction, assays that are easily confused by ATPase and other spurious activities that might arise through "site-directed damage" of the natural kinases being engineered. This article introduces three assays that can detect the formation of both natural and unnatural deoxyribonucleoside triphosphates, assessing their value as polymerase substrates at the same time as monitoring the progress of kinase engineering. Here, we focus on two complementary AEGIS nucleoside diphosphates, 6-amino-5-nitro-3- (1'-B-D-2'-deoxyribofuranosyl)-2(1H)-pyridone and 2-amino-8-(1'-B-D-2'-deoxyribofuranosyl)-imidazo[1,2-a]-1,3,5-triazin- 4(8H)-one. These assays provide new ways to detect the formation of unnatural deoxyribonucleoside triphosphates in vitro and to confirm their incorporation into DNA. Thus, these assays can be used with other unnatural nucleotides.

Crystal structures of deprotonated nucleobases from an expanded DNA alphabet
Mariko F. Matsuura, Hyo-Joong Kim, Daisuke Takahashi, Khalil A. Abboud and Steven A. Benner
Structural Chemistry , Acta Crystallographica (2016) C72, 952-959. doi: 10.1107/S2053229616017071
<Abstract>

Reported here is the crystal structure of a heterocycle that implements a donor–donor–acceptor hydrogen-bonding pattern, as found in the Z component [6-amino-5-nitropyridin-2(1H)-one] of an artificially expanded genetic information system (AEGIS). AEGIS is a new form of DNA from synthetic biology that has six replicable nucleotides, rather than the four found in natural DNA. Remarkably, Z crystallizes from water as a 1:1 complex of its neutral and deprotonated forms, and forms a ‘skinny’ pyrimidine–pyrimidine pair in this structure. The pair resembles the known intercalated cytosine pair. The formation of the same pair in two different salts, namely poly[[aqua(µ6-2-amino-6-oxo-3-nitro-1,6-dihydropyridin-1-ido)sodium]–6-amino-5-nitropyridin-2(1H)-one–water (1/1/1)], denoted Z-Sod, {[Na(C5H4N3O3)(H2O)]·C5H5N3O3·H2O}n, and ammonium 2-amino-6-oxo-3-nitro-1,6-dihydropyridin-1-ide–6-amino-5-nitropyridin-2(1H)-one–water (1/1/1), denoted Z-Am, NH4+·C5H4N3O3·C5H5-N3O3·H2O, under two different crystallization conditions suggests that the pair is especially stable. Implications of this structure for the use of this heterocycle in artificial DNA are discussed.

Evolution of functional six-nucleotide DNA
Zhang, L., Yang, Z., Sefah, K., Bradley, K. M., Hoshika, S., Kim, M-J,. Kim, H-J., Zhu., Jimenez, E., Cansiz, S., Teng, I-T., Champanhac, C, McLendon, C., Liu, C., Zhang, W., Gerloff, D. L., Huang, Z., Tan, W., Benner, S. A.
J. Am. Chem. Soc. (2015) DOI: 10.1021/jacs.5b02251
<Abstract>

Axiomatically, the density of information stored in DNA, with just four nucleotides (GACT), is higher than in a binary code, but less than it might be if synthetic biologists succeed in adding independently replicating nucleotides to genetic systems. Such addition could also add additional functional groups, not found in natural DNA but useful for molecular performance. Here, we consider two new nucleotides (Z and P, 6-amino-5- nitro-3-(1'-B-D-2'-deoxyribo-furanosyl)-2(1H)-pyridone and 2-amino-8-(1'-B-D-2'-deoxyribofuranosyl)-imidazo- [1,2-a]-1,3,5-triazin-4(8H)-one). These are designed to pair via strict Watson?Crick geometry. These were added to a laboratory in vitro evolution (LIVE) experiment; the GACTZP library was challenged to deliver molecules that bind selectively to liver cancer cells, but not to untransformed liver cells. Unlike in classical in vitro selection systems, low levels of mutation allow this system to evolve to create binding molecules not necessarily present in the original library. Over a dozen binding species were recovered. The best had Z and/or P in their sequences. Several had multiple, nearby, and adjacent Zs and Ps. Only the weaker binders contained no Z or P at all. This suggests that this system explored much of the sequence space available to this genetic system and that GACTZP libraries are richer reservoirs of functionality than standard libraries.

Transcription, Reverse Transcription, and Analysis of RNA Containing Artificial Genetic Components
Nicole A. Leal, Hyo-Joong Kim, Shuichi Hoshika, Myong-Jung Kim, Matthew A. Carrigan, and Steven A. Benner
ACS Synthetic Biology , American Chemical Society (2015) Apr 17;4(4):407-13. doi: 10.1021/sb500268n
<Abstract>

Expanding the synthetic biology of artificially expanded genetic information systems (AEGIS) requires tools to make and analyze RNA molecules having added nucleotide "letters". We report here the development of T7 RNA polymerase and reverse transcriptase to catalyze transcription and reverse transcription of xNA (DNA or RNA) having two complementary AEGIS nucleobases, 6-amino-5-nitropyridin-2-one (trivially, Z) and 2-aminoimidazo[1,2a]-1,3,5-triazin-4(8H)-one (trivially, P). We also report MALDI mass spectrometry and HPLC-based analyses for oligomeric GACUZP six-letter RNA and the use of ribonuclease (RNase) A and T1 RNase as enzymatic tools for the sequence-specific degradation of GACUZP RNA. We then applied these tools to analyze the GACUZP and GACTZP products of polymerases and reverse transcriptases (respectively) made from DNA and RNA templates. In addition to advancing this 6-letter AEGIS toward the biosynthesis of proteins containing additional amino acids, these experiments provided new insights into the biophysics of DNA.

A Crystal Structure of a Functional RNA Molecule Containing an Artificial Nucleobase Pair
Armando R. Hernandez, Yaming Shao, Shuichi Hoshika, Zunyi Yang, Sandip A. Shelke, Julien Herrou, Hyo-Joong Kim, Myong-Jung Kim, Joseph A. Piccirilli, and Steven A. Benner
Angew. Chem. Int. Ed. 54 9853-9856 (2015) doi: 10.1002/anie.201504731
<Abstract>

As one of its goals, synthetic biology seeks to increase the number of building blocks in nucleic acids. While efforts towards this goal are well advanced for DNA, they have hardly begun for RNA. Herein, we present a crystal structure for an RNA riboswitch where a stem C:G pair has been replaced by a pair between two components of an artificially expanded genetic-information system (AEGIS), Z and P, (6- amino-5-nitro-2(1H)-pyridone and 2-aminoimidazo[ 1,2-a]-1,3,5-triazin-4-(8H)-one). The structure shows that the Z:P pair does not greatly change the conformation of the RNAmolecule nor the details of its interaction with a hypoxanthine ligand. This was confirmed in solution by in-line probing, which also measured a 3.7 nm affinity of the riboswitch for guanine. These data show that the Z:P pair mimics the natural Watson-Crick geometry in RNA in the first example of a crystal structure of an RNA molecule that contains an orthogonal added nucleobase pair.

Ribonucleosides for an Artificially Expanded Genetic Information System
Hyo-Joong Kim, Nicole A. Leal, Shuichi Hoshika, Steven A. Benner
J. Org. Chem. (2014) 79 (7), pp 3194-3199
<Abstract>

Rearranging hydrogen bonding groups adds nucleobases to an artificially expanded genetic information system (AEGIS), pairing orthogonally to standard nucleotides. We report here a large-scale synthesis of the AEGIS nucleotide carrying 2-amino-3-nitropyridin-6-one (trivially Z) via Heck coupling and a hydroboration/oxidation sequence. RiboZ is more stable against epimerization than its 2?-deoxyribo analogue. Further, T7 RNA polymerase incorporates ZTP opposite its Watson?Crick complement,imidazo[1,2-a]-1,3,5-triazin-4(8H)one (trivially P), laying grounds for using this "second-generation" AEGIS Z:P pair to add amino acids encoded by mRNA.

The "strong" RNA world hypothesis. Fifty years old.
Neveu, Mark; Kim, Hyo-Joong; Benner, Steven A
Astrobiology 13 (4) (2013) DOI: 10.1089/ast.2012.0868
<Abstract>

This year marks the 50th anniversary of a proposal by Alex Rich that RNA, as a single biopolymer acting in two capacities, might have supported both genetics and catalysis at the origin of life. We review here both published and previously unreported experimental data that provide new perspectives on this old proposal. The new data include evidence that, in the presence of borate, small amounts of carbohydrates can fix large amounts of formaldehyde that are expected in an environment rich in carbon dioxide. Further, we consider other species, including arsenate, arsenite, phosphite, and germanate, that might replace phosphate as linkers in genetic biopolymers. While linkages involving these oxyanions are judged to be too unstable to support genetics on Earth, we consider the possibility that they might do so in colder semi-aqueous environments more exotic than those found on Earth, where cosolvents such as ammonia might prevent freezing at temperatures well below 273 K. These include the ammonia-water environments that are possibly present at low temperatures beneath the surface of Titan, Saturn’s largest moon.

Synthesis and Properties of 5-Cyano-Substituted Nucleoside Analog with a Donor-Donor-Acceptor Hydrogen-Bonding Pattern
Hyo-Joong Kim, Fei Chen, and Steven A. Benner
J. Org. Chem. (2012)
<Abstract>

6-Aminopyridin-2-ones form Watson-Crick pairs with complementary purine analogues to add a third nucleobase pair to DNA and RNA, if an electron-withdrawing group at position 5 slows oxidation and epimerization. In previous work with a nucleoside analogue trivially named dZ, the electron withdrawing unit was a nitro group. Here, we describe an analogue of dZ (cyano-dZ) having a cyano group instead of a nitro group, including its synthesis, pKa, rates of acid-catalyzed epimerization, and enzymatic incorporation.

(View publication page for Hyo-Joong Kim)

Associate
Hyo-Joong Kim

Education

Research summary

Recent Publications

Interests

Contact

Associate Hyo-Joong Kim

Education

Research summary

Recent Publications

Interests

Contact

Associate
Hyo-Joong Kim