The crystal structure of a heptameric archaeal Sm protein: Implications for the eukaryotic snRNP core

Sec1p/Munc18 (SM) proteins are essential for SNARE-mediated membrane trafficking. The formulation of unifying hypotheses for the function of the SM protein family has been hampered by the observation that two of its members bind their cognate syntaxins (Sxs) in strikingly different ways. The SM protein Vps45p binds its Sx Tlg2p in a manner analogous to that captured by the Sly1p–Sed5p crystal structure, whereby the NH2-terminal peptide of the Sx inserts into a hydrophobic pocket on the outer face of domain I of the SM protein. In this study, we report that although this mode of interaction is critical for the binding of Vps45p to Tlg2p, the SM protein also binds Tlg2p-containing SNARE complexes via a second mode that involves neither the NH2 terminus of Tlg2p nor the region of Vps45p that facilitates this interaction. Our findings point to the possibility that SM proteins interact with their cognate SNARE proteins through distinct mechanisms at different stages in the SNARE assembly/disassembly cycle.

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Crystal structure of an archaeal Sm protein from Sulfolobus solfataricus

Proteins Structure Function and Bioinformatics ◽

10.1002/prot.20637 ◽

2005 ◽

Vol 61 (3) ◽

pp. 689-693 ◽

Cited By ~ 8

Author(s):

Turgay Kilic ◽

Stéphane Thore ◽

Dietrich Suck

Keyword(s):

Crystal Structure ◽

Sulfolobus Solfataricus ◽

Sm Protein

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An Hfq-like protein in archaea: Crystal structure and functional characterization of the Sm protein from Methanococcus jannaschii

RNA ◽

10.1261/rna.689007 ◽

2007 ◽

Vol 13 (12) ◽

pp. 2213-2223 ◽

Cited By ~ 52

Author(s):

J. S. Nielsen ◽

A. Boggild ◽

C. B.F. Andersen ◽

G. Nielsen ◽

A. Boysen ◽

...

Keyword(s):

Crystal Structure ◽

Functional Characterization ◽

Methanococcus Jannaschii ◽

Sm Protein

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The spliceosomal snRNP core complex of Trypanosoma brucei: Cloning and functional analysis reveals seven Sm protein constituents

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.150236097 ◽

2000 ◽

Vol 97 (16) ◽

pp. 8967-8972 ◽

Cited By ~ 40

Author(s):

Z. Palfi ◽

S. Lucke ◽

H.-W. Lahm ◽

W. S. Lane ◽

V. Kruft ◽

...

Keyword(s):

Functional Analysis ◽

Trypanosoma Brucei ◽

Core Complex ◽

Sm Protein ◽

Snrnp Core

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Spliceosomal U snRNP Core Assembly: Sm Proteins Assemble onto an Sm Site RNA Nonanucleotide in a Specific and Thermodynamically Stable Manner

Molecular and Cellular Biology ◽

10.1128/mcb.19.10.6554 ◽

1999 ◽

Vol 19 (10) ◽

pp. 6554-6565 ◽

Cited By ~ 82

Author(s):

Veronica A. Raker ◽

Klaus Hartmuth ◽

Berthold Kastner ◽

Reinhard Lührmann

Keyword(s):

Protein Interactions ◽

Minimal System ◽

Structural Elements ◽

Small Nuclear Rna ◽

Sm Proteins ◽

Stable Manner ◽

Nuclear Rna ◽

Sm Protein ◽

Kinetics Of ◽

Snrnp Core

ABSTRACT The association of Sm proteins with U small nuclear RNA (snRNA) requires the single-stranded Sm site (PuAU4–6GPu) but also is influenced by nonconserved flanking RNA structural elements. Here we demonstrate that a nonameric Sm site RNA oligonucleotide sufficed for sequence-specific assembly of a minimal core ribonucleoprotein (RNP), which contained all seven Sm proteins. The minimal core RNP displayed several conserved biochemical features of native U snRNP core particles, including a similar morphology in electron micrographs. This minimal system allowed us to study in detail the RNA requirements for Sm protein-Sm site interactions as well as the kinetics of core RNP assembly. In addition to the uridine bases, the 2′ hydroxyl moieties were important for stable RNP formation, indicating that both the sugar backbone and the bases are intimately involved in RNA-protein interactions. Moreover, our data imply that an initial phase of core RNP assembly is mediated by a high affinity of the Sm proteins for the single-stranded uridine tract but that the presence of the conserved adenosine (PuAU…) is essential to commit the RNP particle to thermodynamic stability. Comparison of intact U4 and U5 snRNAs with the Sm site oligonucleotide in core RNP assembly revealed that the regions flanking the Sm site within the U snRNAs facilitate the kinetics of core RNP assembly by increasing the rate of Sm protein association and by decreasing the activation energy.

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Crystal Structure Determination of Glycerol-Containing Lipids from Electron Diffraction Data. Use of Analog Compounds Based upon Configurational Isomers of Cyclopentane-1, 2, 3-TRIOL

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100077761 ◽

1977 ◽

Vol 35 ◽

pp. 24-25

Author(s):

Douglas L. Dorset ◽

Anthony J. Hancock

Keyword(s):

Crystal Structure ◽

Electron Diffraction ◽

Diffraction Data ◽

Structure Determination ◽

Crystal Surface ◽

Coherent Scattering ◽

Crystal Structure Determination ◽

Electron Diffraction Data ◽

Polar Group ◽

Axis Orientation

Lipids containing long polymethylene chains were among the first compounds subjected to electron diffraction structure analysis. It was only recently realized, however, that various distortions of thin lipid microcrystal plates, e.g. bends, polar group and methyl end plane disorders, etc. (1-3), restrict coherent scattering to the methylene subcell alone, particularly if undistorted molecular layers have well-defined end planes. Thus, ab initio crystal structure determination on a given single uncharacterized natural lipid using electron diffraction data can only hope to identify the subcell packing and the chain axis orientation with respect to the crystal surface. In lipids based on glycerol, for example, conformations of long chains and polar groups about the C-C bonds of this moiety still would remain unknown.One possible means of surmounting this difficulty is to investigate structural analogs of the material of interest in conjunction with the natural compound itself. Suitable analogs to the glycerol lipids are compounds based on the three configurational isomers of cyclopentane-1,2,3-triol shown in Fig. 1, in which three rotameric forms of the natural glycerol derivatives are fixed by the ring structure (4-7).

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Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100076263 ◽

1983 ◽

Vol 41 ◽

pp. 518-519

Author(s):

George G. Cocks ◽

Louis Leibovitz ◽

DoSuk D. Lee

Keyword(s):

Crystal Structure ◽

Crassostrea Virginica ◽

Crystal Orientation ◽

Developmental Changes ◽

Gastrula Stage ◽

Orthorhombic Crystal ◽

Orthorhombic Crystal Structure ◽

Stages Of Growth ◽

Early Stages ◽

Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

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Transmission Electron Microscopy studies of the vacancy ordering in YSI2-X thin films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100087124 ◽

1991 ◽

Vol 49 ◽

pp. 562-563

Author(s):

F.-R. Chen ◽

T. L. Lee ◽

L. J. Chen

Keyword(s):

Crystal Structure ◽

Electron Microscopy ◽

Thin Films ◽

Diffraction Pattern ◽

Annealing Temperature ◽

Lattice Mismatch ◽

Si Substrate ◽

Metal Thin Films ◽

Transmission Electron ◽

Vacancy Ordering

YSi2-x thin films were grown by depositing the yttrium metal thin films on (111)Si substrate followed by a rapid thermal annealing (RTA) at 450 to 1100°C. The x value of the YSi2-x films ranges from 0 to 0.3. The (0001) plane of the YSi2-x films have an ideal zero lattice mismatch relative to (111)Si surface lattice. The YSi2 has the hexagonal AlB2 crystal structure. The orientation relationship with Si was determined from the diffraction pattern shown in figure 1(a) to be and . The diffraction pattern in figure 1(a) was taken from a specimen annealed at 500°C for 15 second. As the annealing temperature was increased to 600°C, superlattice diffraction spots appear at position as seen in figure 1(b) which may be due to vacancy ordering in the YSi2-x films. The ordered vacancies in YSi2-x form a mesh in Si plane suggested by a LEED experiment.

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Crystal Structure Analysis of Cu-Zr Alloys by Convergent Beam Diffraction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100098277 ◽

1981 ◽

Vol 39 ◽

pp. 354-355

Author(s):

A. F. Marshall ◽

J. W. Steeds ◽

D. Bouchet ◽

S. L. Shinde ◽

R. G. Walmsley

Keyword(s):

Crystal Structure ◽

Point Group ◽

Intermetallic Phase ◽

Three Dimensional ◽

Crystal Structure Analysis ◽

Ion Milling ◽

Composition And Structure ◽

Unit Cells ◽

Sputter Deposited ◽

Convergent Beam

Convergent beam electron diffraction is a powerful technique for determining the crystal structure of a material in TEM. In this paper we have applied it to the study of the intermetallic phases in the Cu-rich end of the Cu-Zr system. These phases are highly ordered. Their composition and structure has been previously studied by microprobe and x-ray diffraction with sometimes conflicting results.The crystalline phases were obtained by annealing amorphous sputter-deposited Cu-Zr. Specimens were thinned for TEM by ion milling and observed in a Philips EM 400. Due to the large unit cells involved, a small convergence angle of diffraction was used; however, the three-dimensional lattice and symmetry information of convergent beam microdiffraction patterns is still present. The results are as follows:1) 21 at% Zr in Cu: annealed at 500°C for 5 hours. An intermetallic phase, Cu3.6Zr (21.7% Zr), space group P6/m has been proposed near this composition (2). The major phase of our annealed material was hexagonal with a point group determined as 6/m.

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