Epitopes described in "SbsB structure and lattice reconstruction unveil Ca2+ triggered S-layer assembly."

Article Authors:Ekaterina Baranova; Rémi Fronzes; Abel Garcia-Pino; Nani Van Gerven; David Papapostolou; Gérard Péhau-Arnaudet; Els Pardon; Jan Steyaert; Stefan Howorka; Han Remaut
Article Title:SbsB structure and lattice reconstruction unveil Ca2+ triggered S-layer assembly.
Reference Detail
Reference ID:1024632
Abstract:S-layers are regular two-dimensional semipermeable protein layers that constitute a major cell-wall component in archaea and many bacteria. The nanoscale repeat structure of the S-layer lattices and their self-assembly from S-layer proteins (SLPs) have sparked interest in their use as patterning and display scaffolds for a range of nano-biotechnological applications. Despite their biological abundance and the technological interest in them, structural information about SLPs is limited to truncated and assembly-negative proteins. Here we report the X-ray structure of the SbsB SLP of Geobacillus stearothermophilus PV72/p2 by the use of nanobody-aided crystallization. SbsB consists of a seven-domain protein, formed by an amino-terminal cell-wall attachment domain and six consecutive immunoglobulin-like domains, that organize into a φ-shaped disk-like monomeric crystallization unit stabilized by interdomain Ca(2+) ion coordination. A Ca(2+)-dependent switch to the condensed SbsB quaternary structure pre-positions intermolecular contact zones and renders the protein competent for S-layer assembly. On the basis of crystal packing, chemical crosslinking data and cryo-electron microscopy projections, we present a model for the molecular organization of this SLP into a porous protein sheet inside the S-layer. The SbsB lattice represents a previously undescribed structural model for protein assemblies and may advance our understanding of SLP physiology and self-assembly, as well as the rational design of engineered higher-order structures for biotechnology.
Reference Type:Literature
PubMed ID:22722836
Journal Volume:487
Article Pages:119-22
Journal ISSN:1476-4687
Article Chemical List:Bacterial Proteins;Immunoglobulins;Membrane Proteins;SbsB protein, Bacillus stearothermophilus;Solutions;Calcium
Article MeSH List:Bacterial Proteins(chemistry; metabolism); Calcium(chemistry; metabolism; pharmacology); Cryoelectron Microscopy; Crystallization(methods); Crystallography, X-Ray; Geobacillus stearothermophilus(chemistry); Immunoglobulins(chemistry); Membrane Proteins(chemistry; metabolism); Models, Molecular; Molecular Dynamics Simulation; Nanostructures(chemistry); Polymerization(drug effects); Protein Structure, Quaternary(drug effects); Protein Structure, Tertiary(drug effects); Solutions
Curation Last Updated:2014-10-03 22:43:52