Angela Y. Lee

New insight into the catalytic mechanism of chorismate mutases from structural studies

Chorismate mutase catalyzes the rearrangement of chorismic acid to prephenic acid, which is the first committed step in the biosynthesis of aromatic amino acids. Its catalytic mechanism has been much studied, but is poorly understood. Recent structural information on enzymes from two species, and on an antibody that catalyzes the same reaction, has shed new light on this topic.

Laurencione, a heterocycle from the red alga Laurencia spectabilis

Abstract Laurencione was isolated from Laurencia spectabilis and its structure determined to be an equilibrium mixture of (±)-2-hydroxy-2-methyldihydrofuran-3-one and 5-hydroxy-2,3-pentanedione. On silica gel, laurencione dimerized to optically inactive, crystalline spiro-bis-pinnaketal, a previously reported natural product of L. pinnatifida .

Kedarcidin chromophore: Structure elucidation of the amino sugar kedarosamine

Abstract The structure of kedarosamine, the amino sugar moiety of kedarcidin chromophore, was established by NMR spectroscopy and X-ray crystallography as 2,4 dideoxy-4-(dimethylamino)-L-fucopyranose. bl

Volutamides A-E, halogenated alkaloids with antifeedant properties from the Atlantic bryozoan Amathia convoluta

Abstract Volutamides A-E (1–5), halogenated alkaloids of amino acid origin, have been isolated from the temperate Atlantic bryozoan Amathia convoluta Lamouroux. The structures of the new compounds were determined by spectral and chemical methods. The absolute stereochemistries of volutamides B and C were established by CD measurements, while the absolute stereochemistries of volutamides D and E could not be established with confidence. Several of the volutamides deterred feeding by potential predators and were toxic toward larvae of a co-occurring hydroid, suggesting that these metabolites form the basis of an effective chemical defense.

Structure of the trypsin-cyclotheonamide A complex: an all-natural approach

Natural products play a crucial role in chemistry, biology, and the rapidly growing area where these two disciplines meet. They are nature’s answer to controlling biological processes with small molecules, and as such they are valued as biochemical probes by biologists and as novel drug templates by pharmaceutical scientists. Contemporary topics such as chemical diversity and structure-based drug design have remarkable parallels in the wealth of the natural products library and the evolutionary imperatives for optimizing potency and specificity. While natural products research is arguably the oldest branch of experimental science, recent developments have transformed the field. The trypsin-cyclotheonamide A story illustrates these changes Ill.