Molecule of the Month: Twenty Years of Molecules
Celebrating the structural biology revolution
The Structural Biology Revolution
Biggest and Best
Exploring the Structure
Evolution in Action
Theodosius Dobzhansky famously said that "Nothing in biology makes sense except in the light of evolution,” and the PDB archive has many examples where you can see that connection first hand. Some evolution happens over millenia--for example, by comparing the sequences of proteins such as globins, we can discover the detailed pedigrees of related organisms. In bacterial drug resistance, we can see evolution that happens in years, as bacteria evolve new methods for evading drugs through mutation and selection of their existing biomachinery.
The structures shown here reveal evolution happening in a matter of days. Researchers subjected a culture of HIV-infected cells to an HIV protease inhibitor, and watched as increasingly resistant versions evolved through mutation and selection. The wild type enzyme at the top (PDB entry 2az8) is strongly blocked by the inhibitor. By switching a leucine to a smaller alanine, the center enzyme (PDB entry 2az9) removes a favorable interaction and is 4-fold resistant to the inhibitor. The one at the bottom (PDB entry 2azc) further tunes the activity of the enzyme with five more sites of mutation and is 30-fold resistant. To explore these structures in more detail, click on the image for an interactive JSMol.
Topics for Further Discussion
- What is your favorite molecule?
- If you're interested in reading about my goals and methods for these Molecule of the Month columns, take a look at this article in the RCSB newsletter.
January 2020, David Goodselldoi:10.2210/rcsb_pdb/mom_2020_1