Acidianus, Sulfolobus and Metallosphaera surface layers: structure, composition and gene expression
Andreas Veith1, Andreas Klingl, Behnam Zolghadr
1Institute of Microbiology and Genetics, Technische Universität Darmstadt, Schnittspahnstrasse 10, 64287 Darmstadt, Germany.
Molecular Microbiology
|June 16, 2009
Summary
The cell walls of Sulfolobales feature protein S-layers made of SlaA and SlaB. These S-layer proteins (SlaA and SlaB) form crystalline arrays, with SlaB anchoring the structure in the membrane.
Area of Science:
- Microbiology
- Structural Biology
- Biochemistry
Background:
- The cell walls of Sulfolobales species are composed of proteinaceous S-layers.
- These S-layers are assembled from two primary polypeptides: SlaA and SlaB.
Purpose of the Study:
- To isolate and characterize the S-layer proteins (SlaA and SlaB) from key Sulfolobales species.
- To investigate the genetic organization and transcriptional regulation of the slaAB genes.
- To elucidate the structural and assembly mechanisms of Sulfolobales S-layers.
Main Methods:
- Isolation of S-layer proteins from Acidianus ambivalens, Sulfolobus solfataricus, and Metallosphaera sedula.
- Analysis of gene transcription using Northern hybridization and PCR experiments.
- Molecular modeling for structural prediction of SlaB.
- Electron microscopy to visualize S-layer protein arrays.
Main Results:
- The slaAB genes are organized as conserved bicistronic operons in Sulfolobales, with differential transcription termination.
- SlaB shows distant similarity to other Crenarchaeota S-layer proteins and possesses a predicted structure including beta sandwich domains, a coiled-coil domain, and a transmembrane helix.
- Electron microscopy revealed crystalline arrays with distinct pore structures, supporting a model of S-layer assembly.
Conclusions:
- The S-layer structure of Sulfolobales is conserved, with bicistronic operons for SlaA and SlaB transcription.
- A proposed model suggests SlaB anchors the S-layer complex in the membrane, while SlaA forms the outer sacculus.
- SlaB is a key structural component with homology to other archaeal S-layer proteins, while SlaA appears unique to Sulfolobales.
More Related Videos
08:09An Aquatic Microbial Metaproteomics Workflow: From Cells to Tryptic Peptides Suitable for Tandem Mass Spectrometry-based Analysis
Published on: September 15, 2015
10:30Soil Lysimeter Excavation for Coupled Hydrological, Geochemical, and Microbiological Investigations
Published on: September 11, 2016
Related Concept Videos
01:23Surface Appendages of Archaea
Archaeal surface appendages are highly specialized structures essential for environmental adaptation, encompassing roles in adhesion, biofilm formation, and motility. Among these appendages, pili and archaella stand out for their distinct morphologies and functionalities, enabling archaea to thrive in diverse and often extreme environments.Pili: Adhesion and Biofilm FormationPili are filamentous structures assembled from pilin protein subunits, primarily contributing to adhesion and biofilm...
01:25Microbial Mats
Microbial communities forming biofilms and mats represent complex, spatially structured ecosystems where metabolic processes are stratified according to light, oxygen, and nutrient gradients. Biofilms are initial colonization stages, only a few millimeters thick, while mature microbial mats can reach centimeter-scale thickness and display intricate vertical organization. Their structural and functional heterogeneity allows microorganisms to occupy distinct ecological niches within a few...
01:27Diversity of Archaea III
Crenarchaeota, a prominent phylum of Archaea, is remarkable for its ability to thrive in extreme environments characterized by high temperatures and acidity. These microorganisms inhabit sulfuric hot springs, volcanic systems, and submarine hydrothermal vents, where temperatures often exceed 100°C. The unique adaptations of Crenarchaeota not only allow survival under such extreme conditions but also provide insights into the mechanisms of life in primordial Earth-like environments.Morphological...
01:24Microbes and Other Elemental Cycles
Microbial activity plays a pivotal role in the biogeochemical cycling of iron and manganese, especially at the redox gradients characteristic of stratified aquatic environments. These cycles are driven by microbial transformations between oxidized and reduced forms of the metals, allowing organisms to exploit them for metabolic energy and structural purposes.Iron Cycling Across Redox GradientsIn neutral, oxygen-rich surface waters, iron is predominantly found in its oxidized, insoluble ferric...
01:29Biosynthesis of Lipids
Microbial membranes exhibit remarkable diversity in lipid composition, reflecting evolutionary adaptations to various environmental conditions. The three domains of life—Bacteria, Archaea, and Eukarya—synthesize membrane lipids through distinct biosynthetic pathways, leading to fundamental structural differences that impact membrane stability, function, and adaptability.Fatty Acid-Based Lipids in Bacteria and EukaryaBacteria and eukaryotes share a common fatty acid biosynthesis pathway, which...
01:29Archaeal Cell Wall
Archaeal cell walls are structurally and compositionally distinct from their bacterial counterparts, lacking the characteristic peptidoglycan layer found in most bacteria. Instead, archaeal cell walls exhibit remarkable diversity, utilizing materials such as pseudomurein, polysaccharides, and proteins to construct their protective outer layers. This structural flexibility is closely tied to archaea's ecological adaptability.S-Layers: The Common Archaeal Cell WallThe S-layer is the most...