Jacobs University Bremen gGmbH
Campus Ring 1 | 28759 Bremen | Germany
Photochemistry - Supramolecular Chemistry - Fluorescent Probes - Antioxidants - Biomolecular Dynamics
Our scientific background lies in the areas of photochemistry, physical-organic chemistry, and radical chemistry. We use the expertise in molecular science to address fundamental problems in the life sciences, for example, the kinetics of protein folding and the natural antioxidant action of vitamin C and E. Our basic research bears implications for several systems of biological and food-industry-related interest and leads frequently to practical applications in pharmaceutical industry and medical diagnostics. Examples are the development of an antioxidant sensor for human blood plasma and the application of novel lifetime-based fluorescence assays for high-throughput screening for drug discovery.
One aspect of our work lies on the synthesis and characterization of organic chromophores and in particular fluorescent probes. Our spectroscopic experience ranges from fast time-resolved techniques (laser-flash photolysis, time-resolved fluorescence, time-correlated single-photon counting) to conventional fluorescence spectroscopy, UV-Vis spectrophotometry and NMR spectroscopy. In addition, we have a keen interest in the development of kinetic models, which includes the analysis of complex kinetic data by advanced computer-based approaches like the development of global fitting and numerical integration routines. An independent section of our research is involved with the area of supramolecular chemistry and nanomolecular science, which has an important interface to the life sciences in the area of nanobiotechnology.
Research Interests in Nanomolecular Science
One focus of our research lies in the field of supramolecular chemistry, which is aimed towards the understanding of molecular interactions to form larger functional assemblies. In many cases, such assemblies can realize macroscopic functions like transport and motion, just on a nanomolecular level. This way, it is possible to design molecular machines, switches, shuttles, or simply containers by using organic chemistry, and using biological systems as models. One of our research projects deals with supramolecular kinetics, which provides infomation on the operational speed of the employed supramolcular systems. For this purposes, time-resolved transient absorption and fluorescence spectroscopy are employed. Most of these motions occur on the timescale of diffusion, in the nanosecond to microsecond range. The second project is aimed towards the design and application of molecular containers, that is, mostly cyclic macromolecules ("host") sufficiently large to encapsulate smaller molecules ("guest"). The resulting host-guest complexes are of interest for drug delivery systems, analytical purposes, and for catalyzing new chemical reactions inside the host. The molecular containers of interest are cyclodextrins, calixarenes, and cucurbiturils. We have developed special synthetic strategies to obtain derivatives of different sizes, and we apply them in the construction of photonic devices. The third project involves nanomolecules of biological interest, mostly short polypeptides and oligonucleotides. We have developed a probe/quencher technique to measure the flexibility of such short polymers, which affords essentially a material property at the molecular level. Knowing the flexibility of a peptide, for examples, plays a crucial role for predicting the sequence and speed of protein folding, for identifying active sites in proteins, and for facilitating the de-novo design of peptide mimics. Finally, we are merging the area of supramolecular and biological chemistry by investigating hybrid materials composed of a biopolymer which is capped by molecular container molecules at both chain ends, thereby introducing entirely novel properties, e.g., by modifying the activity of substrates towards enzymes. Several of the investigated labeled peptides have found application in high-throughput screening assays in pharmaceutical industry and have proven useful in the drug discovery process.
- M.Sc. in Physical Chemistry, St. Francis Xavier University, Canada (1992)
- Ph.D. in Organic Chemistry, University of Würzburg, Germany (1994)
- Postdoctoral Fellow, University of Ottawa, Canada (1994-1996)
- Habilitation in Chemistry, University of Basel, Switzerland (1996-1999)
- SNF Assistant Professor of Chemistry, University of Basel, Switzerland (since 2000)
- Fellowship of the Studienstiftung des Deutschen Volkes (90/91)
- Faculty Prizes at the University of Wuerzburg (89 and 94)
- Kekule Fellowship of the Fonds der Chemischen Industrie (92-94)
- Studienabschluss-Stipendium of the Fonds der Chemischen Industrie (94)
- NATO Fellowship of the DAAD (94/95)
- Canada International Fellowship of NSERC, Canada (94/95)
- Liebig Fellowship of the Fonds der Chemischen Industrie (96-98)
- Profil-Fellowship of the Swiss National Science Foundation (98-00)
- International Grammaticakis-Neumann Prize (99)
- SNF Professorship of the Swiss National Science Foundation (since 00)
- ADUC Prize (01)
- Werner Prize of the Swiss Chemical Society (02)
- 07.98-10.98W. F. James Chair Professor of Pure and Applied Sciences at St. Francis Xavier University in Antigonish, Nova Scotia, Canada
- 08.01-12.01Margaret L. and Harlan L. Goering Professor in Organic Chemistry at the University of Wisconsin in Madison, USA
- 03.02-06.02Visiting Professor of Chemistry at the International University Bremen
- SNF Assistant Professor of Chemistry, University of Basel, Switzerland (since 2000)
- Professor of Chemistry, International University Bremen, Germany (since 2002)
- H. Bakirci, X. Zhang, W. M. Nau, "Induced Circular Dichroism and Structural Assignment of the b-Cyclodextrin Inclusion Complexes of Bicyclic Azoalkanes", J. Org. Chem. 2005, 70, 39-46.
- J. Mohanty, W. M. Nau, "Ultrastable Rhodamine with Cucurbituril", Angew. Chem. 2005, 117, 38163820; "Ultrastable Rhodamine with Cucurbituril", Angew. Chem. Int. Ed. 2005, 44, 3750-3754.
- W. M. Nau, J. Mohanty, "Taming Fluorescent Dyes with Cucurbituril", Intern. J. Photoenergy 2005, 7, 133-141.
- H. Bakirci, W. M. Nau, "Chiral Resolution through Precipitation of Diastereomeric Capsules in the Form of 2:1 b-Cyclodextrin-Guest Complexes", J. Org. Chem. 2005, 70, 4506-4509.
- H. Bakirci, W. M. Nau, "Chiral Discrimination in the Complexation of Heptakis(2,6-di-O-methyl)-b-cyclodextrin with 2,3-Diazabicyclo[2.2.2]oct-2-ene Derivatives", J. Photochem. Photobiol. A: Chem. 2005, 173, 340-348.
- F. Huang, W. M. Nau, "Photochemical Techniques for Studying the Flexibility of Polypeptides", Res. Chem. Intermed. 2005, 31, 717-726.
- A. L. Koner, N. Singhal, W. M. Nau, J. N. Moorthy, "Substituent Electronic Effects on the Persistence and Absorption Spectra of (Z)-o-Xylylenols. A Nanosecond Laser Flash Photolysis Study", J. Org. Chem. 2005, 70, 7439-7442.
- N. Singhal, A. L. Koner, P. Mal, P. Venugopalan, W. M. Nau, J. N. Moorthy, "Diastereomer-Differentiating Photochemistry of b-Arylbutyrophenones: Yang Cyclization versus Type II Elimination", J. Am. Chem. Soc. 2005, 127, 14375-14382.
- A. F.-P. Sonnen, H. Bakirci, T. Netscher, W. M. Nau, "Effect of Temperature, Cholesterol Content, and Antioxidant Structure on the Mobility of Vitamin E Constituents in Biomembrane Models Studied by Laterally Diffusion-Controlled Fluorescence Quenching", J. Am. Chem. Soc. 2005, 127, 15575-15584.
- H. Bakirci, A. L. Korner, W. M. Nau, "Binding of inorganic cations by p-sulfonatocalixarene monitored through competitive fluorophore displacement in aqueous solution", Chem. Commun. 2005, 5411-5413.
- H. Bakirci, A. L. Korner, W. M. Nau, "Spherical Shape Complementarity as an Overriding Motif in the Molecular Recognition of Noncharged Organic Guests by p-Sulfonatocalixarene: Complexation of Bicyclic Azoalkanes", J. Org. Chem. 2005, 70, 9960-9966.
- W. M. Nau, U. Pischel, "Photoreactivity of n,p*-Excited Azoalkanes and Ketones" in Molecular and Supramolecular Photochemistry, V. Ramamurthy, K. S. Schanze, Eds., Volume 9, 2005, 75-129.
- H. Bakirci, W. M. Nau, "Fluorescence Regeneration as Signaling Principle for Choline and Carnitine Binding: A Refined Supramolecular Sensor System Based on a Fluorescent Azoalkane", Adv. Funct. Mat. 2006, 16, 237-242.
- U. Pischel, D. Patra, A. L. Koner, W. M. Nau, "Investigation of Polar and Stereoelectronic Effects on Pure Excited-State Hydrogen Atom Abstractions from Phenols and Alkylbenzenes", Photochem. Photobiol. 2006, 82, 310-317.
- J. Mohanty, A. C. Bhasikuttan, W. M. Nau, H. Pal, "Host-Guest Complexation of Neutral Red with Macrocyclic Host Molecules: Contrasting pKa Shifts and Binding Affinities for Cucurbituril and b-Cyclodextrin", J. Phys. Chem. B 2006, 110, 5132-5138.
- C. Vannesjö Lundgren, A. L. Koner, M. Tinkl, U. Pischel, W. M. Nau, "Reaction of Singlet-Excited 2,3-Diazabicyclo[2.2.2]oct-2-ene and tert-Butoxyl Radicals with Aryl-Substituted Benzofuranones", J. Org. Chem. 2006, 71, 1977-1983.
- A. Hennig, D. Roth, T. Enderle, W. M. Nau, "Fast Time-Resolved Fluorescence Protease Assays", ChemBioChem. 2006, 7, 733-737.
- H. Bakirci, A. L. Koner, T. Schwarzlose, W. M. Nau, "Analysis of Host-Assisted Guest Protonation Exemplified for p-Sulfonatocalixarene - Towards Enzyme-Mimetic pKa Shifts", Chem. Eur. J. 2006, 12, 4799-4807.
- H. Sahoo, A. Hennig, W. M. Nau "Temperature-Dependent Loop Formation Kinetics in Flexible Peptides Studied by Time-Resolved Fluorescence Spectroscopy", Intern. J. Photoenergy 2006, 8, 1-9.
- H. Sahoo, D. Roccatano, M. Zacharias, W. M. Nau, "Distance Distributions of Short Polypeptides Recovered by Fluorescence Resonance Energy Transfer in the 10 Å Domain", J. Am. Chem. Soc. 2006, 128, 8118-8119.
- H. Sahoo, W. M. Nau "Phosphorylation-Induced Rigidification of Peptides Probed by Time-Resolved Fluorescence Spectroscopy", Ind. J. Rad. Res. 2006, 3, 104-112.
- N. J. Moorthy, A. L. Koner, S. Samanta, N. Singhal, W. M. Nau, R. G. Weiss "Diastereomeric Discrimination in the Lifetimes of Norrish Type II Triplet 1,4-Biradicals and Stereo-Controlled Partitioning of their Reactivity (Yang Cyclization vs Type II Elimination)" Chem. Eur. J. 2006, 12, 8744-8749.
- H. Bakirci, A. L. Koner, M. H. Dickman, U. Kortz, W. M. Nau, "Dynamically Self-Assembling Metalloenzyme Models Based on Calixarenes", Angew. Chem. 2006, 118, 7560-7564; "Dynamically Self-Assembling Metalloenzyme Models Based on Calixarenes", Angew. Chem. Int. Ed. 2006, 45, 7400-7404.
- A. L. Koner, W. M. Nau, "Cucurbituril Encapsulation of Fluorescent Dyes", Supramol. Chem. 2007, 19, 55-66.
- A. Hennig, M. Florea, D. Roth, T. Enderle, W. M. Nau, "Design of Peptide Substrates for Nanosecond Time-Resolved Fluorescence Assays of Proteases: 2,3-Diazabicyclo[2.2.2]oct-2-ene as a Noninvasive Fluorophore", Anal. Biochem. 2007, 360, 255-265.
- J. Mohanty, H. Pal, A. K. Ray, S. Kumar, W. M. Nau, "Supramolecular Dye Laser with Cucurbituril in Water", ChemPhysChem 2007, 8, 54-56.
- H. Sahoo, W. M. Nau, "Phosphorylation-Induced Conformational Changes in Short Peptides Probed by Fluorescence Resonance Energy Transfer in the 10-Å Domain", ChemBioChem, 2007, 8, 567-573.
- A. Hennig, T. Schwarzlose, W. M. Nau, "Bridgehead Carboxy-Substituted 2,3-Diazabicyclo[2.2.2]oct-2-enes: Synthesis, Fluorescent Propeties, and Host-Guest Complexation", ARKIVOC, 2007, (viii), 341-357.
- D. Roccatano, H. Sahoo, M. Zacharias, W. M. Nau, "Temperature Dependence of Looping Rates in a Short Peptide". J. Phys. Chem. B 2007, 111, 2639-2646.
- A. Hennig, G. Ghale, W. M. Nau, "Effects of Cucurbituril on Protease Activity", Chem. Commun. 2007, 1614-1616.
- C. A. Chesta, J. Mohanty, W. M. Nau, U. Bhattacharjee, R. G. Weiss "New insights into the mechanism of triplet radical-pair combinations. The persistent radical effect masks the distinction between in-cage and out-of-cage processes.", J. Am. Chem. Soc. 2007, 129, 5012-5022.
- A. C. Bhasikuttan, J. Mohanty, W. M. Nau, H. Pal, "Efficient fluorescence enhancement and cooperative binding of an organic dye in a supra-bimolecular host-protein assembly", Angew. Chem. Int. Ed. 2007, 46, in press.
- A. L. Koner, J. Schatz, W. M. Nau, U. Pischel, "Selective Sensing of Citrate by a Supramolecular 1,8-Naphthalimide/Calixarene Assembly via Complexation-modulated pKa Shifts in a Ternary Complex", J. Org. Chem. 2007, 72 ,3889-3895.
- A. Hennig, H. Bakirci, W. M. Nau, "Label-Free Continuous Enzyme Assays based on Macrocyclic Fluorescent Dye Complexes", submitted.
- H. Sahoo, D. Roccatano, A. Hennig, W. M. Nau "A Spectroscopic Ruler for Short Polyprolines", J. Am. Chem. Soc. 2007, 129, submitted
- T. Nam, C. L. Rector, H. Kim, A. F.-P. Sonnen, R. Meyer, W. M. Nau, J. Atkinson, J. Rintoul, D. A. Pratt, N. A. Porter, "Tetrahydro-1,8-Naphthyridinol Analogues of a-Tocopherol as Antioxidants in Lipid Membranes and Low Density Lipoproteins", J. Am. Chem. Soc. 2007, 129, submitted.
- W. M. Nau, A. Hennig, A. L. Koner, "Squeezing Fluorescent Dyes into Nanoscale Containers The Supramolecular Approach to Radiative Decay Engineering" in Springer Series on Fluorescence, M. N. Berberan-Santos, Ed., Volume 4, 2007, in press.
- K. Nau-Staudt, W. M. Nau, K. Wunderlich, I.O. Haefliger, J. Flammer, "Antioxidant Activity of Porcine Retina: Dependence on Iris Pigmentation", submitted.