Protein domain repeats within a protein sequence have been observed throughout all domains of life. Our analysis shows a significantly higher degree of sequence identity between repeated domains in prokaryotes compared to eukaryotes. We discuss this difference in the light of aggregation prevention, contribution to functional divergence and binding-related functions. We then address the possible underlying features that create and conserve domain repeats. Our findings provide a starting point for the identification of the fundamental principles that underlie this basic difference between eukaryotic and prokaryotic protein evolution.
Bibliographical noteFunding Information:
We thank Liran Carmel for helpful suggestions, Ed Bayer for an introduction into the cohesin field, and the members of the O.S.F. laboratory for helpful discussions. This work was supported by the Israel Science Foundation founded by the Israel Academy of Science and Humanities (grant number 306/6).