This week in PLOS Biology

In PLOS Biology this week you can read about metabolome evolution, protein flexibility and interactions between proteases and their inhibitors.

In their new research paper, Katarzyna Bozek, Philipp Khaitovich and colleagues analysed thousands of metabolites from brain, kidney and muscle tissue of humans, chimps and monkeys. They found accelerated evolution of metabolites not only in the human brain – which might be expected – but also human muscle metabolomes. The physiological impact of the surprisingly rapid evolution of human muscle remains unclear, although the authors did do a follow up study testing strength in humans and non-human primates and found human strength was barely half that of primates. Read more in the accompanying synopsis.

Proteins often interact with other proteins and assemble into complexes.  Joseph Marsh and Sarah Teichmann computationally assessed the structural flexibility of thousands of proteins in their research article, and found that the flexibility of individual proteins aids their evolutionary recruitment into complexes with increasing numbers of distinct subunits. This flexibility becomes increasingly important as a greater number of proteins are packed together within a single complex.

Proteases (enzymes that break down other proteins) are an important target for drug development, as deregulated protease activity is a common characteristic of many diseases. However we have incomplete understanding of their biology due in part to their complex functions: some activate other proteases whereas some inactivate inhibitors. Network modelling of interactions between proteases and their inhibitors, carried out by Nikolaus Fortelny, Christopher Overall and colleagues reveals a network of new protein connections and cascades in the protease web. They also tested some of the predicted effects in mice.