Fellow

Daniel Hutter

Education

• MS in Chemistry. Swiss Federal Institute of Technology (ETH), Zurich, Switzerland (1994)
• PhD in Chemistry. ETH, Zurich, Switzerland (2001)

Research summary

Synthetic biology. I synthesized DNA oligonucleotides containing modified backbone linkers and studied their duplex conformation and stability. The results obtained have significant implications for gene therapy as well as for the search for life beyond Earth. I also synthesized nucleosides exhibiting hydrogen bonding patterns different from those found in natural DNA, giving rise to an artificially expanded genetic information system with more than just two base pairs. The vast variety of possible applications includes many medical diagnostic tools inaccessible through natural DNA alone.

Personalized medicine. Genetically based side effects from drugs could be managed if it would be possible to sequence the entire genome of an individual patient in a short time (a few days at most) and at low cost (a few thousand dollars). This would vastly increase the range of available drugs. Current methods for sequencing DNA are not able to match these goals. I am synthesizing modified nucleoside triphosphates for highly parallel sequencing technologies on micro arrays that would slash price and time of current methods by several orders of magnitude. In a related project I am developing an improved synthetic method for the fast, clean and selective transformation of nucleosides into their respective triphosphates.

Dynamic combinatorial synthesis. This concept should greatly increase the speed for finding leads in drug discovery. Instead of a scientist designing a drug to a particular enzymatic target, the enzyme itself synthesizes its preferred ligand from two combinatorial libraries of small molecules that are in dynamic equilibrium with each other. These libraries have to exhibit several specific properties, however, that render the successful application of this concept non-trivial. I am currently synthesizing different libraries that are promising candidates.

Publications

Incorporation of Multiple Sequential Pseudothymidines by DNA Polymerases and Their Impact on DNA Duplex Structure
Havemann, SA Hoshika, S Hutter, D Benner, SA
Nuc. Nuc. Nuc. acids 27 (3) 261-278 (2008)
<Abstract>

In this article, we focus on the synthesis of aryl C-glycosides via Heck coupling. It is organized based on the type of structures used in the assembly of the C-glycosides (also called C-nucleosides) with the following subsections: pyrimidine C-nucleosides, purine C-nucleosides, and monocyclic, bicyclic, and tetracyclic C-nucleosides. The reagents and conditions used for conducting the Heck coupling reactions are discussed. The subsequent conversion of the Heck products to the corresponding target molecules and the application of the target molecules are also described.

Synthesis of pyrophosphates for in vitro selection of catalytic RNA molecules
Kim, HJ Kim, MJ Karalkar, N Hutter, D Benner, SA
Nuc. Nuc. Nuc. acids 27 43-56 (2008)

Artificially expanded genetic information system: a new base pair with an alternative hydrogen bonding pattern
Yang, ZY Hutter, D Sheng, PP Sismour, AM Benner, SA
Nucl. Acids Res. 34 (21) 6095-6101 (2006)
<Abstract>

To support efforts to develop a 'synthetic biology' based on an artificially expanded genetic information system (AEGIS), we have developed a route to two components of a non-standard nucleobase pair, the pyrimidine analog 6-amino-5-nitro-3-(1'-beta-D-2'-deoxyribofuranosyl)-2(1H)-pyridone (dZ) and its Watson-Crick complement, the purine analog 2-amino-8-(1'-beta-D-2'-deoxyribofuranosyl)-imidazo[1,2-a]-1,3,5-triazin -4(8H)-one (dP). These implement the pyDDA:puAAD hydrogen bonding pattern (where 'py' indicates a pyrimidine analog and 'pu' indicates a purine analog, while A and D indicate the hydrogen bonding patterns of acceptor and donor groups presented to the complementary nucleobases, from the major to the minor groove). Also described is the synthesis of the triphosphates and protected phosphoramidites of these two nucleosides. We also describe the use of the protected phosphoramidites to synthesize DNA oligonucleotides containing these AEGIS components, verify the absence of epimerization of dZ in those oligonucleotides, and report some hybridization properties of the dZ:dP nucleobase pair, which is rather strong, and the ability of each to effectively discriminate against mismatches in short duplex DNA.

Expanding the genetic alphabet: Non-epimerizing nucleoside with the pyDDA hydrogen-bonding pattern
Hutter, D Benner, SA
J. Org. Chem. 68 (25) 9839-9842 (2003)
<Abstract>

6-Amino-3-(2'-deoxy-beta-D-ribofuranosyl)-5-nitro-1H-pyridin-2-one (4), a C-glycoside exhibiting the nonstandard pgammaDDA hydrogen-bonding pattern, was synthesized via Heck coupling. The nitro group greatly enhances the stability of the nucleoside toward acid-catalyzed epimerization without leading to significant deprotonation of the heterocycle at physiological pH. These results make nucleoside 4 a promising candidate for an expanded genetic alphabet.

Synthetic biology with artificially expanded genetic information systems. From personalized medicine to extraterrestrial life
Benner, SA Hutter, D Sismour, AM
Nucleic Acids Res. Suppl. 3 125-126 (2003)
<Abstract>

Over 15 years ago, the Benner group noticed that the DNA alphabet need not be limited to the four standard nucleotides known in natural DNA. Rather, twelve nucleobases forming six base pairs joined by mutually exclusive hydrogen bonding patterns are possible within the geometry of the Watson-Crick pair (Fig. 1). Synthesis and studies on these compounds have brought us to the threshold of a synthetic biology, an artificial chemical system that does basic processes needed for life (in particular, Darwinian evolution), but with unnatural chemical structures. At the same time, the artificial genetic information systems (AEGIS) that we have developed have been used in FDA-approved commercial tests for managing HIV and hepatitis C infections in individual patients, and in a tool that seeks the virus for severe acute respiratory syndrome (SARS). AEGIS also supports the next generation of robotic probes to search for genetic molecules on Mars, Europa, and elsewhere where NASA probes will travel.

Phosphates, DNA, and the search for nonterrean life: A second generation model for genetic molecules
Benner, SA Hutter, D
Bioorg. Chem. 30 (1) 62-80 (2002)
<Abstract>

Phosphate groups are found and used widely in biological chemistry. We have asked whether phosphate groups are likely to be important to the functioning of genetic molecules. including DNA and RNA. From observations made on synthetic analogs of DNA and RNA where the phosphates are replaced by nonanionic linking groups, we infer a set of rules that highlight the importance of the phosphodiester backbone for the proper functioning of DNA as a genetic molecule. The polyanionic backbone appears to give DNA the capability of replication following simple rules, and evolving. The polyanionic nature of the backbone appears to be critical to prevent the single strands from folding. permitting them to act as templates, guiding the interaction between two strands to form a duplex in a way that permits simple rules to guide the molecular recognition event, and buffering the sensitivity of its physicochemical properties to changes in sequence. We argue that the feature of a polyelectrolyte (polyanion or polycation) may be required for a "self-sustaining chemical system capable of Darwinian evolution." The polyelectrolyte structure therefore may be a universal signature of life, regardless of its genesis. and unique to living forms as well. (C) 2002 Elsevier Science (USA).

From phosphate to bis(methylene) sulfone: Non-ionic backbone linkers in DNA
Hutter, D Blaettler, MO Benner, SA
Helv. Chim. Acta 85 (9) 2777-2806 (2002)
<Abstract>

Chimeric DNA molecules containing four different linking groups, the natural phosphate, 5'-methylenephosphonate. bis(methylene)phosphinate, and bis(methylene) sulfone (see Fig.1), were directly compared for their ability to form duplexes with complementary DNA and DNA chimeras. From melting temperatures for analogous complementary sequences, general conclusions about the impact of geometric distortion of the internucleotide linkage around the two P-O-C bridges were drawn, as were conclusions about the impact on duplex stability that arises from the removal of the negative charge in the linking group. Each structural perturbation diminished the melting temperature, by ca. -2.5degrees per modification for the 5'-methylenephosphonate, -3.5degrees per modification for the bis(methylene)phosphinate, and -4.5degrees per modification for the bis(methylene) sulfone linker. These results have implications for DNA chemistry including the design of 'antisense' candidates and the proposal of alternative genetic materials in the search for non-terrean life.

Redesigning nucleic acids
Benner, SA Battersby, TR Eschgfaller, B Hutter, D Kodra, JT Lutz, S Arslan, T Baschlin, DK Blattler, M Egli, M Hammer, C Held, HA Horlacher, J Huang, Z Hyrup, B Jenny, TF Jurczyk, SC Konig, M von Krosigk, U Lutz, MJ MacPherson, LJ Moroney, SE Muller, E Nambiar, KP Piccirilli, JA Switzer, CY Vogel, JJ Richert, C Roughton, AL Schmidt, J Schneider, KC Stackhouse, J
Pure Appl. Chem. 70 (2) 263-266 (1998)
<Abstract>

A research program has applied the tools of synthetic organic chemistry to systematically modify the structure of DNA and RNA oligonucleotides to learn more about the chemical principles underlying their ability to store and transmit genetic information. Oligonucleotides (as opposed to nucleosides) have long been overlooked by synthetic organic chemists as targets for structural modification. Synthetic chemistry has now yielded oligonucleotides with 12 replicatable letters, modified backbones, and new insight into why Nature chose the oligonucleotide structures that she did.