Unraveling CapG: A Staph Enzyme's Unfolding Story

CapG, a key enzyme from Staphylococcus aureus, folds and unfolds in a complex dance. This protein, which helps the bacteria build its defence shield, changes shape based on its concentration and surroundings. Scientists studied a replica of CapG, called rCapG, and found it can exist in many forms, from solo (monomers) to grouped (oligomers like dimers, trimers, tetramers, and hexamers). At low concentrations, rCapG is mostly alone, but as it gets crowded, it prefers to hang out in threes (trimers). When stressed with a chemical called urea, rCapG starts to come apart. It forms three unique intermediate states, each one more dissolved than the last. The two parts of rCapG, its N-terminal and C-terminal domains, start unfolding at the same time, but the C-terminal domain finishes the job first. This study shines a light on how CapG behaves and folds, which could help find new ways to fight Staph infections in the future.