Cooperativity is the basis for a variety of microscopic events, such as the simultaneous chelation of metal ions, the temporal coordination of protein folding and the concerted function of biomolecular assemblies. At the macroscale, cooperation between scientific laboratories, organizations and countries is required to advance research in a timely manner and to coordinate conferences and funding initiatives. The whole process of nutrition to food science to farming to sales in shops to cooking food to eating to metabolising the food is another important Cooperativity process.
Cooperativity is most usually applied to small-molecule properties and enzyme behavior. The cooperative function of hemoglobin was first documented in 1925 by Gilbert Adair. Similarly, the term ‘chelate’ was first coined in 1920, with subsequent investigations into host molecules such as clathrates and cryptands.
Today Cooperativity encompasses a range of scientific systems and is an umbrella term for processes such as preorganization, avidity, allostery and some types of assembly. Cooperativity can also be more broadly defined as a process for which intermediates are disfavoured (resulting, for example, in a two-state conformational change).
However as knowledge increases on processes it becomes less clear that a particular process is cooperative as compared to simply proceeding along a downward energetic trajectory or occurring at an observed rate. Similarly, according to this broad definition, complicated processes such as cytokinesis can be considered cooperative in that in the absence of perturbants or disruptive mutations, halting at an intermediate state is disfavored. As our mechanistic insight into biological systems grows, scientists must be mindful not to apply the term too loosely to processes that are simply coordinated in space or time (like cell division or signaling cascades), but rather they must look for those systems that are directly energetically linked.
These diverse examples accentuate the importance of looking at cooperativity from new angles, in allowing us to formulate hypotheses about increasingly complex systems and in helping to provide a firm scientific grounding for discussions about larger scale phenomena such as emergent properties
A recent edition of Nature Chemical Biology is a exciting review of processes and concepts which are central to so much in nutrition. Chemical biology itself provides an important reflection of cooperativity, since the field has grown through collaboration and openness to new ideas and approaches. This issue, features pieces exploring molecular, cellular and organismal cooperativity, providing further thought as to how the mechanisms of seemingly divergent systems intersect.
Editorial Nature Chemical Biology 4, 433 (2008
- Martin Eastwood