title: Intersubunit linker length as a modifier of protein stability: crystal structures and thermostability of mutant TRAP.
abstract: The ability of proteins to self-assemble into complex, functional nanoscale structures is expected to become of significant use in the manufacture of artificial nanodevices with a wide range of novel applications. The bacterial protein TRAP has potential uses as a nanoscale component as it is ring-shaped, with a central, modifiable cavity. Furthermore, it can be engineered to make a ring of 12-fold symmetry, which is advantageous for packing into two-dimensional arrays. The 12mer form of TRAP is made by linking multiple subunits together on the same polypeptide, but the usefulness of the 12mers described to date is limited by their poor stability. Here we show that, by altering the length of the peptide linker between subunits, the thermostability can be significantly improved. Since the subunit interfaces of the different 12mers are essentially identical, stabilization arises from the reduction of strain in the linkers. Such a simple method of controlling the stability of modular proteins may have wide applications, and demonstrates the lack of absolute correlation between interactions observable by crystallography and the internal energy of a complex.
authors.affiliation: Protein Design Laboratory, Yokohama City University, Tsurumi, Yokohama 230-0045, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Watanabe
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Mishima
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yamashita
authors.forename: Sam-Yong
authors.initials: SY
authors.lastname: Park
authors.forename: Jeremy R H
authors.initials: JR
authors.lastname: Tame
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Heddle
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002151:Calorimetry; D018360:Crystallography, X-Ray; D050939:Gene Fusion; D008958:Models, Molecular; D009154:Mutation; D036103:Nanotechnology; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics; D012313:RNA / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013696:Temperature; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C079092:MtrB protein, Bacteria; D021122:Protein Subunits; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D012313:RNA