The Size of Homomeric Complexes in the Protein Data Bank and in SwissProt

<p>The histogram shows the relative abundances of monomers and homo-oligomers of different sizes in the PDB and in SwissProt. Two PDB sets are shown: the complete set and the nonredundant set of QSs. Three SwissProt sets are shown: the complete SwissProt and the Human and E. coli subsets. The trend in all the sets is similar and highlights the importance of the mechanism of self-assembly, which is linked to many functional possibilities discussed in the text. The oligomeric state of proteins in SwissProt was extracted from the subunit annotation field, and annotations inferred by similarity were not considered.