Chemical biologists build molecules to interrogate living cells
Biochemistry asks what chemistry goes on inside living things. Chemical biology flips the question, using synthetic molecules as tools to probe and steer cells, from sugars that tag cell surfaces to two-headed drugs that drag a target protein toward the cell's own disposal system.
The field sits between chemistry and biology and is often mistaken for biochemistry, but its focus is different: applying chemical techniques, and especially small molecules made in the lab, to biological questions. Though it feels modern, the name was already in print in 1907, in Alonzo E. Taylor's book On Fermentation, and John B. Leathes used it in a 1930 lecture on the birth of chemical biology. The field gained dedicated journals only recently, with Nature Chemical Biology founded in 2005 and ACS Chemical Biology in 2006.
Its roots go deeper. In 1828 Friedrich Wöhler made urea, a compound from living bodies, from inorganic starting materials, undermining vitalism, the belief that organic substances needed a living source. Later in the century Friedrich Miescher extracted a substance he called nuclein from the nuclei of white blood cells and analysed it chemically; it was later renamed DNA, and his work laid groundwork for the double helix.
Modern practice is inventive. Because sugars are not written directly in the genome, chemists feed cells synthetic versions of natural sugars to study them, and Carolyn Bertozzi's group developed ways to react molecules at precise spots on cell surfaces using such sugars. Proteins can be assembled chemically, piece by piece, to include amino acids nature never uses or modifications like phosphorylation; a technique called native chemical ligation stitches short synthetic fragments into full-length chains with a natural bond. Activity-based probes, built from inhibitors that bind irreversibly, label only the enzymes that are actually working.
Some tools repurpose biology itself. DNA can template chemical reactions, self-assembling proteins can scaffold new materials, and RNA can be evolved in the test tube to catalyse reactions. Two-sided small molecules such as PROTACs pull two proteins together inside a cell, which can be used to trigger the targeted destruction of a chosen protein.
Source: Chemical biology
