title: Comparison of in vivo selection and rational design of heterodimeric coiled coils.
abstract: To investigate how electrostatic interactions restrict the associations of coiled coils, we improved a heterodimeric coiled coil (WinZip-A1B1) by in vivo selection and, alternatively, by rational design. Selection from libraries encoding variable edge (g and e) residues enriched g/e' ion pairs, but the optimum selected heterodimers unexpectedly retained two predicted repulsive g/e' pairs. The best genetically selected heterodimer displayed similar thermodynamic stability and specificity as a rationally designed dimer with predicted ion pairs at all edge positions. This rationally designed pair, however, was less effective than the best genetically selected pair in mediating dimerization in vivo. Thus, the effects of predicted charge pairs depend on sequence context, and complementary charges at the edge positions rationalize only a fraction of the sequences that form stable, specific coiled coils.
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
authors.forename: Katja M
authors.initials: KM
authors.lastname: Arndt
authors.forename: Joelle N
authors.initials: JN
authors.lastname: Pelletier
authors.forename: Kristian M
authors.initials: KM
authors.lastname: Müller
authors.forename: Andreas
authors.initials: A
authors.lastname: Plückthun
authors.forename: Tom
authors.initials: T
authors.lastname: Alber
mesh_terms: D002455:Cell Division; D002478:Cells, Cultured; D002942:Circular Dichroism; D019281:Dimerization; D019020:Directed Molecular Evolution; D015195:Drug Design; D004795:Enzyme Stability; D006860:Hydrogen Bonding; D007700:Kinetics; D008958:Models, Molecular; D015202:Protein Engineering; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D055672:Static Electricity; D013696:Temperature; D013762:Tetrahydrofolate Dehydrogenase / Q000737:chemistry* / Q000378:metabolism*; D013816:Thermodynamics
chemical_list: D013762:Tetrahydrofolate Dehydrogenase