title: Investigation at residue level of the early steps during the assembly of two proteins into supramolecular objects.
abstract: Understanding the driving forces governing protein assembly requires the characterization of interactions at molecular level. We focus on two homologous oppositely charged proteins, lysozyme and α-lactalbumin, which can assemble into microspheres. The assembly early steps were characterized through the identification of interacting surfaces monitored at residue level by NMR chemical shift perturbations by titrating one (15)N-labeled protein with its unlabeled partner. While α-lactalbumin has a narrow interacting site, lysozyme has interacting sites scattered on a broad surface. The further assembly of these rather unspecific heterodimers into tetramers leads to the establishment of well-defined interaction sites. Within the tetramers, most of the electrostatic charge patches on the protein surfaces are shielded. Then, hydrophobic interactions, which are possible because α-lactalbumin is in a partially folded state, become preponderant, leading to the formation of larger oligomers. This approach will be particularly useful for rationalizing the design of protein assemblies as nanoscale devices.
authors.affiliation: Laboratoire de Chimie et Biologie des Métaux, CEA-Grenoble , Grenoble, France.
authors.forename: Delphine B
authors.initials: DB
authors.lastname: Salvatore
authors.forename: Nicolas
authors.initials: N
authors.lastname: Duraffourg
authors.forename: Adrien
authors.initials: A
authors.lastname: Favier
authors.forename: Bjorn A
authors.initials: BA
authors.lastname: Persson
authors.forename: Mikael
authors.initials: M
authors.lastname: Lund
authors.forename: Marie-Madeleine
authors.initials: MM
authors.lastname: Delage
authors.forename: Robert
authors.initials: R
authors.lastname: Silvers
authors.forename: Harald
authors.initials: H
authors.lastname: Schwalbe
authors.forename: Thomas
authors.initials: T
authors.lastname: Croguennec
authors.forename: Said
authors.initials: S
authors.lastname: Bouhallab
authors.forename: Vincent
authors.initials: V
authors.lastname: Forge
mesh_terms: D000818:Animals; D002417:Cattle; D002645:Chickens; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D007768:Lactalbumin / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008863:Microspheres; D056004:Molecular Dynamics Simulation; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D025941:Protein Interaction Mapping / Q000379:methods*; D055503:Protein Multimerization; D055672:Static Electricity; D013816:Thermodynamics
chemical_list: D007768:Lactalbumin; D009113:Muramidase