A solenoid design for assessing determinants of parallel β-sheet registration.
A novel protein construct is presented that combines a homotrimeric, triple-stranded β-helix as a guest to a homotrimeric foldon unit from bacteriophage T4 fibritin. The β-helical solenoid selected is short (46 residues) and is part of a subdomain of the T4 cell-puncturing device. The resultant design is trimeric and displays greatly enhanced stability over each sub-component alone. The intended goal is a design that will enable evaluation of sequence determinants that promote in-register versus out-of-register parallel β-sheet homotrimerization. Towards that end, the importance of a set of three buried salt-bridges was evaluated by converting them to residues otherwise consistently found throughout the natural solenoid at the same positions. The critical role of the charged residues in the salt-bridges was evident in that their elimination resulted in amyloid-like aggregation.
Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, CT 06520-8114, USA.
Ellen M
EM
White
Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, CT 06520-8114, USA andrew.miranker@yale.edu.
Andrew D
AD
Miranker
D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry; D001671:Biochemistry / Q000379:methods*; D005456:Fluorescent Dyes; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D014764:Viral Proteins / Q000648:ultrastructure*
D000682:Amyloid; D005456:Fluorescent Dyes; D014764:Viral Proteins; C057839:fibritin protein, Enterobacteria phage T4
amyloid; foldon; parallel β-sheet; salt-bridge; β-helix