4AQ1

Structure of the SbsB S-layer protein of Geobacillus stearothermophilus PV72p2 in complex with nanobody KB6

Summary for 4AQ1

• Entry DOI: 10.2210/pdb4aq1/pdb
• Descriptor: SBSB PROTEIN, NBKB6, CALCIUM ION, ... (5 entities in total)
• Functional Keywords: structural protein, s-layer protein, nanobody
• Biological source: GEOBACILLUS STEAROTHERMOPHILUS; More
• Total number of polymer chains: 4
• Total formula weight: 218241.67

Authors

Baranova, E.,Remaut, H. (deposition date: 2012-04-12, release date: 2012-06-13, Last modification date: 2024-11-20)

Primary citation

Baranova, E.,Fronzes, R.,Garcia-Pino, A.,Van Gerven, N.,Papapostolou, D.,Pehau-Arnaudet, G.,Pardon, E.,Steyaert, J.,Howorka, S.,Remaut, H.
Sbsb Structure and Lattice Reconstruction Unveil Ca21 Triggered S-Layer Assembly
Nature, 487:119-, 2012

PubMed 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.

PubMed: 22722836
DOI: 10.1038/NATURE11155

Experimental method

X-RAY DIFFRACTION (2.42 Å)