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Stetefeld, Jörg; Jenny, Margrit; Schulthess, Therese; Landwehr, Ruth; Engel, Jürgen; Kammerer, Richard A.

doi:10.1038/79006

Cited by 160 publications

(123 citation statements)

References 28 publications

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“…Dure (23) used computer modeling to predict that Group 3 LEA proteins adopt amphiphilic ␣-helices that dimerize in an unusual right-handed coiled coil arrangement, with a periodicity defined by the 11-mer motif. Right-handed coiled coils based on an 11-mer repeat were later found in a surface layer protein from Staphylothermus marinus (28), demonstrating that this conformation is found in nature. Larger complexes might also arise (29), because a Group 3 LEA-like wheat protein is predicted by the MultiCoil program (30) to form trimeric coiled coils.…”

mentioning

confidence: 99%

Transition from Natively Unfolded to Folded State Induced by Desiccation in an Anhydrobiotic Nematode Protein

Goyal

Tisi

Basran

et al. 2003

Journal of Biological Chemistry

186

187

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Late embryogenesis abundant (LEA) proteins are associated with desiccation tolerance in resurrection plants and in plant seeds, and the recent discovery of a dehydration-induced Group 3 LEA-like gene in the nematode Aphelenchus avenae suggests a similar association in anhydrobiotic animals. Despite their importance, little is known about the structure of Group 3 LEA proteins, although computer modeling and secondary structure algorithms predict a largely ␣-helical monomer that forms coiled coil oligomers. We have therefore investigated the structure of the nematode protein, Aav-LEA1, in the first such analysis of a well characterized Group 3 LEA-like protein. Immunoblotting and subunit cross-linking experiments demonstrate limited oligomerization of AavLEA1, but analytical ultracentrifugation and gel filtration show that the vast majority of the protein is monomeric. Moreover, CD, fluorescence emission, and Fourier transform-infrared spectroscopy indicate an unstructured conformation for the nematode protein. Therefore, in solution, no evidence was found to support structure predictions; instead, Aav-LEA1 seems to be natively unfolded with a high degree of hydration and low compactness. Such proteins can, however, be induced to fold into more rigid structures by partner molecules or by altered physiological conditions. Because AavLEA1 is associated with desiccation stress, its Fourier transform-infrared spectrum in the dehydrated state was examined. A dramatic but reversible increase in ␣-helix and, possibly, coiled coil formation was observed on drying, indicating that computer predictions of secondary structure may be correct for the solid state. This unusual finding offers the possibility that structural shifts in Group 3 LEA proteins occur on dehydration, perhaps consistent with their role in anhydrobiosis.

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mentioning

confidence: 99%

Transition from Natively Unfolded to Folded State Induced by Desiccation in an Anhydrobiotic Nematode Protein

Goyal

Tisi

Basran

et al. 2003

Journal of Biological Chemistry

186

187

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“…Finally, note that between successive 'rings of four' are central cavities, which, as Stetefeld et al [8] point out, may contain water molecules.…”

Section: The Archaeon Surface Protein 4-helix Bundlementioning

confidence: 99%

“…We now consider an α-helix from an archaeon surface protein [8] whose amino acid sequence has an 11-repeat, which may be represented as…”

Section: The Archaeon Surface Protein 4-helix Bundlementioning

confidence: 99%

“…Our three main examples of 4-helix bundles have quite different geometries: the modified GCN4 tetramer of Harbury et al [7] has overall left-handed twist, resembling broadly that of the well-known GCN4 simple coiled coil; tetrabrachion, the tetrameric Staphylothermus marinus surface layer protein [8], hereafter referred to as the 'archaeon surface protein', is like a bundle of four parallel pencils, with zero twist; while the tetramerization domain of the Mnt repressor from the Salmonella bacteriophage P22 has a strong overall right-handed twist and, unlike the other two, has anti-parallel packing [9]. Our interpretation of these structures is that each of them displays knobs-into-holes interfaces, but of three distinct varieties, which are related in a simple geometric way to the repeat pattern of hydrophobic residues in the constituent α-helices.…”

Section: Introductionmentioning

confidence: 99%

“…In such cases, for ease of coding, we 'parallelize' the interface by inverting the order of residues of the second helix (reading it from its C-terminus to N-terminus). 8. In general, our goal is to convert data in the form of such a distance matrix into knobs-into-holes interface 'ladder' patterns of the kind shown in figures 1f , 3f and 4f .…”

mentioning

confidence: 99%

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Geometric principles in the assembly of α-helical bundles

Pratap

Luisi

Calladine

2013

Phil. Trans. R. Soc. A.

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α-Helical coiled coils are usually stabilized by hydrophobic interfaces between the two constituent α-helices, in the form of ‘knobs-into-holes’ packing of non-polar residues arranged in repeating heptad patterns. Here we examine the corresponding ‘hydrophobic cores’ that stabilize bundles of four α-helices. In particular, we study three different kinds of bundle, involving four α-helices of identical sequence: two pack in a parallel and one in an anti-parallel orientation. We point out that the simplest way of understanding the packing of these 4-helix bundles is to use Crick's original idea that the helices are held together by ‘hydrophobic stripes’, which are readily visualized on the cylindrical surface lattice of the α-helices; and that the ‘helix-crossing angle’—which determines, in particular, whether supercoiling is left- or right-handed—is fixed by the slope of the lattice lines that contain the hydrophobic residues. In our three examples the constituent α-helices have hydrophobic repeat patterns of 7, 11 and 4 residues, respectively; and we associate the different overall conformations with ‘knobs-into-holes’ packing along the 7-, 11- and 4-start lines, respectively, of the cylindrical surface lattices of the constituent α-helices. For the first two examples, all four interfaces between adjacent helices are geometrically equivalent; but in the third, one of the four interfaces differs significantly from the others. We provide a geometrical explanation for this non-equivalence in terms of two different but equivalent ways of assembling this bundle, which may possibly constitute a bistable molecular ‘switch’ with a coaxial throw of about 12 Å. The geometrical ideas that we deploy in this paper provide the simplest and clearest description of the structure of helical bundles. In an appendix, we describe briefly a computer program that we have devised in order to search for ‘knobs-into-holes’ packing between α-helices in proteins.

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S ‐Layers

Engelhardt

2016

Encyclopedia of Life Sciences

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Microbial surface layer (S‐layer) proteins assemble into two‐dimensional (2D) crystalline lattices on the cell surface of many species of Archaea and Bacteria and represent the outermost cell wall component, except for the existence of a carbohydrate capsule. Despite their widespread occurrence, the function of S‐layers remained obscure. Analysing the S‐layer structure on the one hand and the interaction of the 2D crystal with the underlying cell membrane on the other, reveals the S‐layers' cell wall function and the mechanism of cell stabilisation in Archaea . This basic function is not obvious in Bacteria . Here, experimental data suggest a major role in mediating and controlling interactions of S‐layers with the microbes' environment. The hybrid functional role of S‐layers will be understood more clearly if structural research is combined with the investigation of S‐layer interactions with the adjacent cell envelope components and the complex environmental factors. Key Concepts Microbial S‐layers have a hybrid functional role, that is, mediating cell stability and controlling cell surface properties. The architecture of S‐layers and their close interactions with the cell membrane determine and explain the S‐layers' cell wall function in Archaea . Attracting and repelling surface characteristics of S‐layers in Bacteria mediate the interactions with the environment and contribute to the proliferation and survival of cells. The investigation of S‐layer functions requires the combined analysis of the S‐layer structure and its impact on the cell envelope components as well as of interactions with environmental factors.

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Cited by 160 publications

References 28 publications

Transition from Natively Unfolded to Folded State Induced by Desiccation in an Anhydrobiotic Nematode Protein

Transition from Natively Unfolded to Folded State Induced by Desiccation in an Anhydrobiotic Nematode Protein

Geometric principles in the assembly of α-helical bundles

S ‐Layers

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