Spontaneous self-assembly of engineered armadillo repeat protein fragments into a folded structure

TitleSpontaneous self-assembly of engineered armadillo repeat protein fragments into a folded structure
Publication TypeJournal Article
Year of Publication2014
AuthorsWatson R.P, Christen M.T, Ewald C., Bumbak F., Reichen C., Mihajlovic M., Schmidt E., Güntert P., Caflisch A., Plückthun A., Zerbe O.
JournalStructure
Volume22
Issue7
Pagination985-995
Date Published2014 Jul 8
Type of ArticleResearch Article
ISSN1878-4186
KeywordsArmadillo Domain Proteins, molecular dynamics, Protein Engineering, Protein Folding, repeat proteins, spontaneous assembly
Abstract

Repeat proteins are built of modules, each of which constitutes a structural motif. We have investigated whether fragments of a designed consensus armadillo repeat protein (ArmRP) recognize each other. We examined a split ArmRP consisting of an N-capping repeat (denoted Y), three internal repeats (M), and a C-capping repeat (A). We demonstrate that the C-terminal MA fragment adopts a fold similar to the corresponding part of the entire protein. In contrast, the N-terminal YM2 fragment constitutes a molten globule. The two fragments form a 1:1 YM2:MA complex with a nanomolar dissociation constant essentially identical to the crystal structure of the continuous YM3A protein. Molecular dynamics simulations show that the complex is structurally stable over a 1 μs timescale and reveal the importance of hydrophobic contacts across the interface. We propose that the existence of a stable complex recapitulates possible intermediates in the early evolution of these repeat proteins.

DOI10.1016/j.str.2014.05.002
pubindex

0187

Alternate JournalStructure
PubMed ID24931467