Carmelo J. Rizzo, Ph.D.
Professor of Chemistry
Director of Graduate Studies
Vanderbilt University, Chemistry Department
7330 Stevenson Ctr
Nashville, TN 37235-1822
Synthesis of oligonucleotides containing structurally defined carcinogen adducts: The first step of chemical carcinogenesis is the covalent modification of DNA with electrophiles. If these modifications are not repaired, they may compromise the fidelity of DNA replication leading to mutations and possibly cancer. To better understand the structure, mutagenicity and repair of such DNA-carcinogen adducts, we are developing synthetic methods for the preparation of oligonucleotides that have been modified by a carcinogen. The challenge of this work is that the carcinogen adduct must be incorporated site-specifically and in a stereochemically defined manner. We have develop an efficient route for the preparation of C8-deoxyguanosine adducts of mutagenic amines, such as those found in cooked meats. One example is the food mutagen known as IQ, which has been shown to be a potent mutagen in the Ames assay. A second class of DNA adducts we are synthesizing are those from a,b-unsaturated aldehydes which are products of lipid peroxidation. One example of such an endogenous genotoxin is 4-hydroxynonenal (4-HNE) which form exocyclic adducts with deoxyguanosine, deoxyadenosine and deoxycytidine. The reaction of 4-Hydroxynonenal with deoxyguanosine gives four stereoisomeric products. We have developed a strategy for the site-specific and stereospecific syntheses of oligonucleotides containing covalent 4-HNE adducts. This will allow us to examine the role of stereochemistry in the structure and biological activity of these adducts.
Chemical Models for Flavoenzyme Catalysis: Flavoenzymes mediate a wide variety of reaction types making them unique biological catalysts. The organic cofactors responsible for their chemical properties are derivatives of riboflavin (vitamin B2). While a tremendous body of literature now exists on flavin chemistry and biochemistry, the mechanism by which specific interactions between the cofactor and the protein environment modulate the redox and catalytic properties of riboflavin is still not fully understood. We are synthesizing chemical models that mimic specific interactions between the flavin and protein and evaluating how these interactions modulate the redox and catalytic properties of flavin cofactors. The conformation of free flavin is believed to be depended upon the oxidation state of the cofactor. We have synthesized conformationally biased flavin models and showed that the redox chemistry can be driven by conformational consideration. We have also synthesized flavin models with specific hydrogen bonds to the flavin nucleus. A growing number of flavinproteins have been identified in which the cofactors is covalently modified. In the case of some C6-modified flavin cofactors, the covalent modification appears to be an inactivation pathway. We are interested in examining the mechanism by which covalent bonds are form between the C6-position of the cofactor and the substrate during catalysis.
- Stover, JS, Ciobanu, M, Cliffel, DE, Rizzo, CJ Chemical and electrochemical oxidation of C8-arylamine adducts of 2''-deoxyguanosine. J Am Chem Soc, 129(7), 2074-81, 2007.
- Elmquist, CE, Wang, F, Stover, JS, Stone, MP, Rizzo, CJ Conformational Differences of the C8-Deoxyguanosine Adduct of 2-Amino-3-methylimidazo[4,5-f]quinoline (IQ) within the NarI Recognition Sequence. Chem Res Toxicol, 2007.
- Cho, YJ, Kozekov, ID, Harris, TM, Rizzo, CJ, Stone, MP Stereochemistry Modulates the Stability of Reduced Interstrand Cross-Links Arising from R- and S-alpha-CH(3)-gamma-OH-1,N(2)-Propano-2''-deoxyguanosine in the 5''-CpG-3'' DNA Sequence. Biochemistry, 46(10), 2608-21, 2007.
- Wang, F, DeMuro, NE, Elmquist, CE, Stover, JS, Rizzo, CJ, Stone, MP Base-displaced intercalated structure of the food mutagen 2-amino-3-methylimidazo[4,5-f]quinoline in the recognition sequence of the NarI restriction enzyme, a hotspot for -2 bp deletions. J Am Chem Soc, 128(31), 10085-95, 2006.
- Choi, JY, Stover, JS, Angel, KC, Chowdhury, G, Rizzo, CJ, Guengerich, FP Biochemical basis of genotoxicity of heterocyclic arylamine food mutagens: Human DNA polymerase eta selectively produces a two-base deletion in copying the N2-guanyl adduct of 2-amino-3-methylimidazo[4,5-f]quinoline but not the C8 adduct at the NarI G3 site. J Biol Chem, 281(35), 25297-306, 2006.
- Otteneder, MB, Knutson, CG, Daniels, JS, Hashim, M, Crews, BC, Remmel, RP, Wang, H, Rizzo, C, Marnett, LJ In vivo oxidative metabolism of a major peroxidation-derived DNA adduct, M1dG. Proc Natl Acad Sci U S A, 103(17), 6665-9, 2006.
- Cho, YJ, Wang, H, Kozekov, ID, Kozekova, A, Kurtz, AJ, Jacob, J, Voehler, M, Smith, J, Harris, TM, Rizzo, CJ, Lloyd, RS, Stone, MP Orientation of the crotonaldehyde-derived N2-[3-Oxo-1(S)-methyl-propyl]-dG DNA adduct hinders interstrand cross-link formation in the 5''-CpG-3'' sequence. Chem Res Toxicol, 19(8), 1019-29, 2006.
- Wang, H, Kozekov, ID, Kozekova, A, Tamura, PJ, Marnett, LJ, Harris, TM, Rizzo, CJ Site-specific synthesis of oligonucleotides containing malondialdehyde adducts of deoxyguanosine and deoxyadenosine via a postsynthetic modification strategy. Chem Res Toxicol, 19(11), 1467-74, 2006.
- Cho, YJ, Wang, H, Kozekov, ID, Kurtz, AJ, Jacob, J, Voehler, M, Smith, J, Harris, TM, Lloyd, RS, Rizzo, CJ, Stone, MP Stereospecific Formation of Interstrand Carbinolamine DNA Cross-Links by Crotonaldehyde- and Acetaldehyde-Derived alpha-CH(3)-gamma-OH-1,N(2)-Propano-2''-deoxyguanosine Adducts in the 5''-CpG-3'' Sequence. Chem Res Toxicol, 19(2), 195-208, 2006.
- Choi, JY, Zang, H, Angel, KC, Kozekov, ID, Goodenough, AK, Rizzo, CJ, Guengerich, FP Translesion synthesis across 1,N2-ethenoguanine by human DNA polymerases. Chem Res Toxicol, 19(6), 879-86, 2006.
- Stover, JS, Chowdhury, G, Zang, H, Guengerich, FP, Rizzo, CJ Translesion synthesis past the C8- and N2-deoxyguanosine adducts of the dietary mutagen 2-Amino-3-methylimidazo[4,5-f]quinoline in the NarI recognition sequence by prokaryotic DNA polymerases. Chem Res Toxicol, 19(11), 1506-17, 2006.
- Zang, H, Goodenough, AK, Choi, JY, Irimia, A, Loukachevitch, LV, Kozekov, ID, Angel, KC, Rizzo, CJ, Egli, M, Guengerich, FP DNA adduct bypass polymerization by Sulfolobus solfataricus DNA polymerase Dpo4: analysis and crystal structures of multiple base pair substitution and frameshift products with the adduct 1,N2-ethenoguanine. J Biol Chem, 280(33), 29750-64, 2005.
- Goodenough, AK, Kozekov, ID, Zang, H, Choi, JY, Guengerich, FP, Harris, TM, Rizzo, CJ Site specific synthesis and polymerase bypass of oligonucleotides containing a 6-hydroxy-3,5,6,7-tetrahydro-9H-imidazo[1,2-a]purin-9-one base, an intermediate in the formation of 1,N2-etheno-2''-deoxyguanosine. Chem Res Toxicol, 18(11), 1701-14, 2005.
- Cho, YJ, Kim, HY, Huang, H, Slutsky, A, Minko, IG, Wang, H, Nechev, LV, Kozekov, ID, Kozekova, A, Tamura, P, Jacob, J, Voehler, M, Harris, TM, Lloyd, RS, Rizzo, CJ, Stone, MP Spectroscopic characterization of interstrand carbinolamine cross-links formed in the 5''-CpG-3'' sequence by the acrolein-derived gamma-OH-1,N2-propano-2''-deoxyguanosine DNA adduct. J Am Chem Soc, 127(50), 17686-96, 2005.
- Scholdberg, TA, Merritt, WK, Dean, SM, Kowalcyzk, A, Harris, CM, Harris, TM, Rizzo, CJ, Lloyd, RS, Stone, MP Structure of an oligodeoxynucleotide containing a butadiene oxide-derived N1 beta-hydroxyalkyl deoxyinosine adduct in the human N-ras codon 61 sequence. Biochemistry, 44(9), 3327-37, 2005.
- Wang, H, Marnett, LJ, Harris, TM, Rizzo, CJ A novel synthesis of malondialdehyde adducts of deoxyguanosine, deoxyadenosine, and deoxycytidine. Chem Res Toxicol, 17(2), 144-9, 2004.
- Brock, AK, Kozekov, ID, Rizzo, CJ, Harris, TM Coupling products of nucleosides with the glyoxal adduct of deoxyguanosine. Chem Res Toxicol, 17(8), 1047-56, 2004.
- West, JD, Ji, C, Duncan, ST, Amarnath, V, Schneider, C, Rizzo, CJ, Brash, AR, Marnett, LJ Induction of apoptosis in colorectal carcinoma cells treated with 4-hydroxy-2-nonenal and structurally related aldehydic products of lipid peroxidation. Chem Res Toxicol, 17(4), 453-62, 2004.
- Elmquist, CE, Stover, JS, Wang, Z, Rizzo, CJ Site-specific synthesis and properties of oligonucleotides containing C8-deoxyguanosine adducts of the dietary mutagen IQ. J Am Chem Soc, 126(36), 11189-201, 2004.
- Stover, JS, Rizzo, CJ Synthesis of the N2-deoxyguanosine adduct of the potent dietary mutagen IQ. Org Lett, 6(26), 4985-8, 2004.
- Kozekov, ID, Nechev, LV, Moseley, MS, Harris, CM, Rizzo, CJ, Stone, MP, Harris, TM DNA interchain cross-links formed by acrolein and crotonaldehyde. J Am Chem Soc, 125(1), 50-61, 2003.
- Wang, H, Kozekov, ID, Harris, TM, Rizzo, CJ Site-specific synthesis and reactivity of oligonucleotides containing stereochemically defined 1,N2-deoxyguanosine adducts of the lipid peroxidation product trans-4-hydroxynonenal. J Am Chem Soc, 125(19), 5687-700, 2003.
- Guo, F, Chang, BH, Rizzo, CJ An N1-hydrogen bonding model for flavin coenzyme. Bioorg Med Chem Lett, 12(2), 151-4, 2002.
- Nechev, LV, Kozekov, ID, Brock, AK, Rizzo, CJ, Harris, TM DNA adducts of acrolein: site-specific synthesis of an oligodeoxynucleotide containing 6-hydroxy-5,6,7,8-tetrahydropyrimido[1,2-a]purin-10(3H)-one, an acrolein adduct of guanine. Chem Res Toxicol, 15(5), 607-13, 2002.
- Wang, F, Wang, H, Polavarapu, PL, Rizzo, CJ Absolute configuration and conformational stability of (+)-2,5-dimethylthiolane and (-)-2,5-dimethylsulfolane. J Org Chem, 66(10), 3507-12, 2001.
- Rizzo, CJ Further computational studies on the conformation of 1,5-dihydrolumiflavin. Antioxid Redox Signal, 3(5), 737-46, 2001.
- Wang, H, Rizzo, CJ Stereocontrolled syntheses of all four stereoisomeric 1,N2-deoxyguanosine adducts of the lipid peroxidation product trans-4-hydroxynonenal. Org Lett, 3(22), 3603-5, 2001.
- Wang, Z, Rizzo, CJ Synthesis of the C8-deoxyguanosine adduct of the food mutagen IQ. Org Lett, 3(4), 565-8, 2001.
- Wang, Z, Rizzo, CJ Regioselective synthesis of beta-N1- and beta-N3-alloxazine nucleoside. Org Lett, 2(2), 227-30, 2000.
- Wang, Z, Prudhomme, DR, Buck, JR, Park, M, Rizzo, CJ Stereocontrolled syntheses of deoxyribonucleosides via photoinduced electron-transfer deoxygenation of benzoyl-protected ribo- and arabinonucleosides. J Org Chem, 65(19), 5969-85, 2000.
- Reibenspies, JH, Guo, F, Rizzo, CJ X-ray crystal structures of conformationally biased flavin models. Org Lett, 2(7), 903-6, 2000.
- Hasford, JJ, Rizzo, CJ "A Linear Free Energy Substituent Effect on Flavin Redox Chemistry." J. Am. Chem. Soc., 120(10), 2251-55, 1998.
- Prudhomme, DR, Wang, Z, Rizzo, CJ An Improved Photosensitizer for the Photoinduced Electron-Transfer Deoxygenation of Benzoates and m-(Trifluoromethyl)benzoates. J Org Chem, 62(23), 8257-8260, 1997.
- Hasford, JJ, Kemnitzer, W,Rizzo, CJ "Conformational Effects on Flavin Redox Chemistry." J. Org. Chem., 62(16), 5244-5, 1997.
- Park, M, Rizzo, CJ Stereocontrolled de Novo Synthesis of beta-2'-Deoxyribonucleosides. J Org Chem, 61(18), 6092-6093, 1996.
- Minnie Park and Carmelo J. Rizzo Stereocontrolled, De Novo Synthesis of beta-2'-Deoxyribonucleosides. J. Org. Chem., 616092-6093, 1996.