Publication Date:
2012-06-23
Description:
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 phi-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.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Baranova, Ekaterina -- Fronzes, Remi -- Garcia-Pino, Abel -- Van Gerven, Nani -- Papapostolou, David -- Pehau-Arnaudet, Gerard -- Pardon, Els -- Steyaert, Jan -- Howorka, Stefan -- Remaut, Han -- BB/E010466/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- England -- Nature. 2012 Jul 5;487(7405):119-22. doi: 10.1038/nature11155.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Structural and Molecular Microbiology, VIB Department of Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22722836" target="_blank"〉PubMed〈/a〉
Keywords:
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
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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