0000000000764572
AUTHOR
Christine Evrard
The first successful crystallization of a prokaryotic extremely thermophilic outer surface layer glycoprotein
AbstractMethanoihermus fervidusbelongs to the group of hyperthermophilic Archaea. The Archaea comprise organisms that live under environmental extremes, like high temperature, lowpH value or high salt concentration. The outer surface of the pseudomurein sacculi of the cells ofMethanothermus fervidusis covered by glycoprotein subunits (S-layer) directly exposed to the extreme environment. The elucidation of the crystal structure of this surface glycoprotein may provide important information on the survival strategies of these unusual micro-organisms. Before our investigations neither three-dimensional crystals have been obtained nor X-ray analyses were performed. Only electron microscopic an…
Primary Structure of Selected Archaeal Mesophilic and Extremely Thermophilic Outer Surface Layer Proteins
The archaea are recognized as a separate third domain of life together with the bacteria and eucarya. The archaea include the methanogens, extreme halophiles, thermoplasmas, Sulfate reducers and Sulfur metabolizing thermophiles, which thrive in different habitats such as anaerobic niches, salt lakes, and marine hydrothermals systems and continental solfataras. Many of these habitats represent extreme environments in respect to temperature, osmotic pressure and pH-values and remind on the conditions of the early earth. The cell envelope structures were one of the first biochemical characteristics of archaea studied in detail. The most common archaeal cell envelope is composed of a single cry…
Molecular organization of selected prokaryotic S-layer proteins.
Regular crystalline surface layers (S-layers) are widespread among prokaryotes and probably represent the earliest cell wall structures. S-layer genes have been found in approximately 400 different species of the prokaryotic domains bacteria and archaea. S-layers usually consist of a single (glyco-)protein species with molecular masses ranging from about 40 to 200 kDa that form lattices of oblique, tetragonal, or hexagonal architecture. The primary sequen ces of hyperthermophilic archaeal species exhibit some characteristic signatures. Further adaptations to their specific environments occur by various post-translational modifications, such as linkage of glycans, lipids, phosphate, and sulf…