News and Publications

Catalytic Antibodies and the Application of Soluble Polymers in Organic Synthesis

* Hoechst Marion Roussel, Inc., Cincinnati, OH

Hydrolysis of phosphodiester bonds, such as those found in DNA and RNA, is a reaction of fundamental importance in living systems. Consequently, intense efforts center on the development of novel phosphodiesterases for use in biochemistry and medicine. Our approach is to exploit the diversity of the murine immune system to generate antibodies with phosphodiesterase activity.

Specifically, we use a charged hapten that elicits a complementary charged residue in the antibody-combining site during the evolutionary timescale of immunization. This counter-charged residue then acts in a catalytic manner when the hapten is "switched" to the substrate in question. Using this strategy, we designed a hapten that generates the key features of general base catalysis used by RNase A (Fig. 1). The rate of catalysis with several isolated catalytic antibodies is only 2 orders of magnitude lower in proficiency than naturally occurring RNase A. Because of these preliminary results, we envisage new hapten designs that incorporate the salient features of both transition-state analog and charge complementarity for the elicitation of antibodies with even more proficient RNase-like activity.

Polymer-supported synthesis of nonpeptide-nonnucleic acid molecules has been growing at an exponential rate. Yet, adaptation of a series of complex reactions from solution to solid-phase synthesis is still in early development. Indeed, polymer-supported total synthesis of natural products has only recently been successful. The prostaglandin family of natural products contains perhaps the most physiologically potent nonprotein molecules found in mammals. Prostaglandins play a vital role in inflammation, tissue repair, and the immune response. Their complex structure and delicate framework have provided a benchmark for chemists interested in demonstrating new synthetic strategies.

From a combinatorial standpoint, polymer-supported synthesis of such molecules ushers in another degree of complexity to the synthetic scheme. Although screening large numbers of such compounds would greatly improve the probability of finding appropriate biological activity, we are using novel soluble polymers to synthesize these complex molecules in a combinatorial format.

Our reasoning is based on ease of purification and flexibility of these supports to adapt to a variety of chemical reactions. Figure 2 shows a prostaglandin E₂ scaffold that we used to synthesize a library of prostaglandin molecules on soluble polymer supports. We anticipate that this library of prostanoid molecules will greatly enhance screening efforts to elucidate new molecules of biological activity.

Publications

Berg, T., Vandersteen, A.M., Janda, K.D. High-throughput synthesis and direct screening for the discovery of novel hydrolytic metal complexes. Bioorg. Med. Chem. Lett. 8:1221, 1998.

Chen, S., Janda, K.D. Total synthesis of naturally occurring prostaglandin F_2α on a non-cross-linked polystyrene support. Tetrahedron Lett. 39:3943, 1998.

Gao, C., Lavey, B.J., Lo, C.-H.L., Datta, A., Wentworth, P., Jr., Janda, K.D. Direct selection for catalysis from combinatorial antibody libraries using a boronic acid probe: Primary amide bond hydrolysis. J. Am. Chem. Soc. 120:2211, 1998.

Gravert, D.J., Janda, K.D. Bifunctional initiators for free radical polymerization of non-crosslinked block copolymers. Tetrahedron Lett. 39:1513, 1998.

Gravert, D.J., Janda, K.D. Organic reactions on soluble polymer supports as an alternative methodology for combinatorial solid-phase synthesis. In: Biotechnology International. Connor, T.H., Hairi, R.J. (Eds.). Universal Medical Press, San Francisco, 1997, p. 169.

Gravert, D.J., Janda, K.D. Soluble polyethylene glycol supports for liquid-phase combinatorial synthesis. Drugs Future 22:1147, 1997.

Gravert, D.J., Janda, K.D. Synthesis on soluble polymers: New reactions and the construction of small molecules. Curr. Opin. Chem. Biol. 1:107, 1998.

Han, H., Yoon, J., Janda, K.D. An efficient asymmetric route to 2,3-diaminobutanoic acids. J. Org. Chem. 63: 2045, 1998.

Han, H., Yoon, J., Janda, K.D. Investigations of azapeptides as mimetics of leu-enkephalin. Bioorg. Med. Chem. Lett. 8:117, 1998.

Hasserodt, J., Janda, K.D. Syntheses of octahydroquinoline-N-oxides: Haptens designed to elicit catalytic antibodies that control a terpenoid-like cascade cyclization. Tetrahedron 53:11237, 1997.

Hasserodt, J., Lerner, R.A., Janda, K.D. Formation of bridge-methylated decalins by antibody-catalyzed tandem cationic cyclization. J. Am. Chem. Soc. 119:5993, 1997.

Heine, A., Stura, E.A., Yli-Kauhaluoma, J.T., Gao, C., Deng, Q., Beno, B.R., Houk, K.N., Janda, K.D., Wilson, I.A. An antibody exo-Diels-Alderase inhibitor complex at 1.95-Å resolution. Science 279:1934, 1998.

Hori, M., Janda, K.D. A soluble polymer approach to the "fishing out" principle: Synthesis and purification of ß-amino alcohols. J. Org. Chem. 63:889, 1998.

Lin, C.-H., Hoffman, T.S., Xie, Y., Wirsching, P., Janda, K.D. An antibody transesterase derived from reactive immunization that utilizes a wide variety of alcohol substrates. J. Chem. Soc. Chem. Commun. 1075, 1998.

Wentworth, P., Jr., Janda, K.D. Catalytic antibodies. Curr. Opin. Chem. Biol. 2:138, 1998.

Wentworth, P., Jr., Janda, K.D. Synthesis of oxorhenium (V) and oxotechnetium (V) complexes as inhibitors of ribonucleases and for the generation of catalytic antibodies. Synlett 5:537, 1997.

Wentworth, P., Jr., Liu, Y., Wentworth, A.D., Fan, P., Foley, M.J., Janda, K.D. A bait and switch hapten strategy generates catalytic antibodies for phosphodiester hydrolysis. Proc. Natl. Acad. Sci. U.S.A. 95:5971, 1998.

Yli-Kauhaluoma, J.T., Harwig, C.W., Wentaorth, P., Jr., Janda, K.D. Unexpected 1,3-oxazolidine formation in the attempted oxidation of N-aryl-N-methyl substituted ß-amino alcohols using pyridinium dichromate. Tetrahedron Lett. 39:2269, 1998.