Topological determinants of protein domain swapping.
Protein domain swapping has been repeatedly observed in a variety of proteins and is believed to result from destabilization due to mutations or changes in environment. Based on results from our studies and others, we propose that structures of the domain-swapped proteins are mainly determined by their native topologies. We performed molecular dynamics simulations of seven different proteins, known to undergo domain swapping experimentally, under mildly denaturing conditions and found in all cases that the domain-swapped structures can be recapitulated by using protein topology in a simple protein model. Our studies further indicated that, in many cases, domain swapping occurs at positions around which the protein tends to unfold prior to complete unfolding. This, in turn, enabled prediction of protein structural elements that are responsible for domain swapping. In particular, two distinct domain-swapped dimer conformations of the focal adhesion targeting domain of focal adhesion kinase were predicted computationally and were supported experimentally by data obtained from NMR analyses.
Ding
Feng
F
Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, North Carolina 27599, USA.
Prutzman
Kirk C
KC
Campbell
Sharon L
SL
Dokholyan
Nikolay V
NV
D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry; D002352:Carrier Proteins / Q000737:chemistry; D003198:Computer Simulation; D019281:Dimerization; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000737:chemistry; D008836:Micrococcal Nuclease / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D017434:Protein Structure, Tertiary / Q000502:physiology*; D012259:Ribonuclease, Pancreatic / Q000737:chemistry; D018909:src Homology Domains / Q000502:physiology
D001426:Bacterial Proteins; D002352:Carrier Proteins; C107733:cyanovirin N; D051416:Focal Adhesion Protein-Tyrosine Kinases; D012259:Ribonuclease, Pancreatic; D008836:Micrococcal Nuclease