A Periodic Table Of Protein Complexes

Understanding and cataloging the huge variety of structures within proteins is extremely important 

In a Longevity Reporter article earlier this year we reported on the publication of the largest map of protein complexes to date. Now in a new study published in the prestigious journal Science researchers report the very first “periodic system” of protein complexes. 

Proteins are essential for life

They are involved in virtually every process that takes place in our body including the breakdown of food, providing structural support to our cells and tissues, generating energy, transporting substances, contraction of our muscles and many more. Many proteins are found in complexes, meaning they are bound together with other proteins of either the same or different sort. The three dimensional structure of these protein complexes is called their quaternary structure. 

Establishing a protein periodic table

The assembly of proteins in vivo (in the body) happens through evolutionarily conserved, ordered pathways. By exploring the assembly pathways the researchers hoped to explain the range of protein complexes found in nature. The researchers analysed tens of thousands of protein complexes for which three dimensional structures had been published, and combined these with new mass spectrometry data. From this analysis it became clear that the assembly steps for protein complexes can be classified in just three basic types. They further showed that 92% of protein complexes found in nature are compatible with their model. The 8% that is incompatible is partially caused by misassignments in published structures. However approximately 4% represent true deviations from the model and the authors are conducting further research on the nature of these special exceptions.  

Interestingly, the researchers predictions allowed regions of quaternary structure space that have not yet been populated; just like the periodic table of the elements, composed by Mendeleev, predicted the existence of novel elements that had not yet been discovered. This data on allowed quaternary space and the stability of protein complexes found in different regions of this space will be of tremendous help to scientists who aim to engineer new protein complexes not found in nature. 

The new ‘periodic table’ of protein complexes can be seen here

Read more at Science Daily