Carbohydrate Chemistry seminars

Carolyn Bertozzi, Morten Meldal and Barry Sharpless explain the development of reliable reactions for connecting molecular components and the extension of those reactions into biological systems. Meldal and Sharpless describe the ideas and discoveries behind click chemistry, including efficient azide–alkyne coupling, and its use as a practical strategy for building functional molecules. Bertozzi addresses the additional challenge of performing chemical reactions in living systems without disrupting their normal processes. Her account connects the study and labelling of cell-surface glycans with the emergence of bioorthogonal chemistry and its biological and medical applications. The lectures distinguish robust synthetic coupling from the further requirements imposed by chemistry in cells and organisms.

Donna Blackmond examines two linked problems in the origin of life: how an initially balanced mixture of molecular mirror images could acquire a handedness bias, and how that small bias could be amplified. She compares four experimental approaches using chemical kinetics and solid–solution equilibria. The first is asymmetric autocatalysis, including the Soai reaction and kinetic models connecting self-replication with suppression of the opposite enantiomer. Blackmond distinguishes this powerful model from a demonstrated prebiotic pathway. She then discusses amplification through eutectic partitioning and through attrition-enhanced deracemization, where dissolution, crystal growth and interconversion can produce a single-handed solid. The final approach incorporates stereochemical selection into plausible prebiotic chemistry. Examples explore reciprocal enrichment involving sugars and amino-acid precursors. The lecture argues that accounts of how biological building blocks arose must explain their chirality alongside their synthesis.