Chemical biology

Chemical biology is a scientific field located at the intersection of chemistry and biology. It applies chemical methods to study complex biological systems. Scientists use chemical techniques and analytical approaches to understand life. They often use small molecules produced through synthetic chemistry to probe biological processes. These tools allow researchers to characterize and manipulate systems at the molecular level. While it overlaps with biochemistry, it has a unique focus. Biochemistry studies the chemistry of biomolecules and how pathways are regulated. In contrast, chemical biology emphasizes the deliberate design of chemical tools to solve biological questions.

One major area of research is glycobiology, which is the study of carbohydrates. Unlike DNA, RNA, or proteins, carbohydrates are not encoded directly by the genome. This makes them harder to study using traditional genetic tools. Chemical biologists develop novel methods to analyze and synthesize these sugars. For example, they can supply cells with synthetic sugar variants to probe their function.

Another method is combinatorial chemistry. This process involves the simultaneous synthesis of many related compounds. This allows for high-throughput analysis, which makes screening for new drugs much more efficient. This approach is also used in agriculture and food research to create novel enzyme inhibitors.

Chemical biologists also use peptide synthesis to build proteins. This allows them to introduce non-natural amino acids into a protein. They can also add post-translational modifications, which are changes made to a protein after it is built. These modifications, such as phosphorylation or glycosylation, regulate how proteins work. To make large protein chains, scientists use native chemical ligation. This process couples a C-terminal thioester with an N-terminal cysteine residue. This results in the formation of a native amide bond.

This chemical approach often has a lower technical barrier than purely biological methods.

The history of this field is rooted in several major discoveries. In 1828, Friedrich Wöhler synthesized urea from inorganic materials. This discovery weakened the idea of vitalism, which claimed life required a special "living" force. Miescher's work in the late 19th century also laid a vital foundation. He investigated human leukocytes and discovered "nuclein," which we now call DNA. The term "chemical biology" appeared in a 1907 book by Alonzo E. Taylor. It was later used in a 1930 article by John B. Leathes. These milestones helped transition biology from observation to active chemical manipulation.

Many breakthroughs in chemical biology have earned Nobel Prizes. In 1980, Paul Berg won for recombinant DNA, and Walter Gilbert and Frederick Sanger won for genome sequencing. In 1993, Kary Mullis and Michael Smith were honored for PCR and site-directed mutagenesis. In 2009, researchers elucidated the structure of the ribosome. In 2012, scientists studied G-protein-coupled receptors. In 2018, Frances Arnold, George Smith, and Gregory Winter were recognized for enzyme development and phage display. In 2020, Jennifer Doudna and Emmanuelle Charpentier won for CRISPR/Cas9 genetic scissors. In 2022, Barry Sharpless, Morten Meldal, and Carolyn Bertozzi were honored for click chemistry. In 2024, Demis Hassabis and John Jumper were recognized for AlphaFold.

A key challenge is performing reactions inside living cells, known as bioorthogonal chemistry. Most laboratory chemical reactions cannot work in a cell because they are sensitive to water or heat. Bioorthogonal reactions must be highly selective and fast. Click chemistry is a perfect example because it is rapid and spontaneous. However, the most famous click reaction requires copper, which is toxic to cells. To solve this, Carolyn Bertozzi used cyclic alkynes to create reactions that work safely in vivo. This allows scientists to label molecules of interest without harming the living system.

Finally, chemical biology connects to the study of entire ecosystems through metagenomics. In the late 1990s, new sequencing technologies allowed scientists to study environmental DNA, or eDNA. This means they can investigate DNA from entire communities of organisms without growing them in a lab. They can sample DNA from soil, oceans, hot springs, and even polar ice caps. This allows the study of organisms that cannot survive in standard laboratory growth conditions. By combining chemistry with genomics, we can explore the most extreme environments on Earth.