scholarly journals Structural analysis of Shigella flexneri bi-functional enzyme HisIE in histidine biosynthesis

2019 ◽  
Vol 516 (2) ◽  
pp. 540-545
Author(s):  
Yannan Wang ◽  
Fan Zhang ◽  
Yan Nie ◽  
Guijun Shang ◽  
Heqiao Zhang
Keyword(s):  
Structural Analysis ◽  
Shigella Flexneri ◽  
Histidine Biosynthesis

scholarly journals In situ structural analysis of the Yersinia enterocolitica injectisome

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Mikhail Kudryashev ◽  
Marco Stenta ◽  
Stefan Schmelz ◽  
Marlise Amstutz ◽  
Ulrich Wiesand ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Yersinia Enterocolitica ◽  
Pathogenic Bacteria ◽  
Protein Complexes ◽  
Shigella Flexneri ◽  
Effector Proteins ◽  
Host Cells ◽  
Dimensional Structure ◽  
Bacterial Cells

Injectisomes are multi-protein transmembrane machines allowing pathogenic bacteria to inject effector proteins into eukaryotic host cells, a process called type III secretion. Here we present the first three-dimensional structure of Yersinia enterocolitica and Shigella flexneri injectisomes in situ and the first structural analysis of the Yersinia injectisome. Unexpectedly, basal bodies of injectisomes inside the bacterial cells showed length variations of 20%. The in situ structures of the Y. enterocolitica and S. flexneri injectisomes had similar dimensions and were significantly longer than the isolated structures of related injectisomes. The crystal structure of the inner membrane injectisome component YscD appeared elongated compared to a homologous protein, and molecular dynamics simulations documented its elongation elasticity. The ring-shaped secretin YscC at the outer membrane was stretched by 30–40% in situ, compared to its isolated liposome-embedded conformation. We suggest that elasticity is critical for some two-membrane spanning protein complexes to cope with variations in the intermembrane distance.

Structural analysis of the surface-layer protein of spirillum serpens by high-resolution electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 738-739
Author(s):  
W. H. Wu ◽  
R. M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Structural Analysis ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Surface Layer Protein ◽  
Morphological Unit ◽  
Resolution Electron

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.

RNA polymerase: Preparation and structural analysis of helical polymers

1984 ◽  
Vol 42 ◽  
pp. 152-153
Author(s):  
E. Loren Buhle ◽  
Pamela Rew ◽  
Ueli Aebi
Keyword(s):  
Structural Analysis ◽  
Rna Polymerase ◽  
Molecular Level ◽  
X Ray Diffraction ◽  
Helical Polymers ◽  
X Ray ◽  
E Coli ◽  
The Past ◽  
Ordered Arrays ◽  
Low Ionic Strength

While DNA-dependent RNA polymerase represents one of the key enzymes involved in transcription and ultimately in gene expression in procaryotic and eucaryotic cells, little progress has been made towards elucidation of its 3-D structure at the molecular level over the past few years. This is mainly because to date no 3-D crystals suitable for X-ray diffraction analysis have been obtained with this rather large (MW ~500 kd) multi-subunit (α2ββ'ζ). As an alternative, we have been trying to form ordered arrays of RNA polymerase from E. coli suitable for structural analysis in the electron microscope combined with image processing. Here we report about helical polymers induced from holoenzyme (α2ββ'ζ) at low ionic strength with 5-7 mM MnCl2 (see Fig. 1a). The presence of the ζ-subunit (MW 86 kd) is required to form these polymers, since the core enzyme (α2ββ') does fail to assemble into such structures under these conditions.

Interpreting HVEM of muscle-cell impulse networks

1992 ◽  
Vol 50 (1) ◽  
pp. 126-127
Author(s):  
Paul DeCosta ◽  
Kyugon Cho ◽  
Stephen Shemlon ◽  
Heesung Jun ◽  
Stanley M. Dunn
Keyword(s):  
Structural Analysis ◽  
Muscle Cell ◽  
Electron Micrographs ◽  
Relative Size ◽  
Automatic Classification ◽  
Nerve Fibers ◽  
Analysis Algorithm ◽  
Structural Networks

Introduction: The analysis and interpretation of electron micrographs of cells and tissues, often requires the accurate extraction of structural networks, which either provide immediate 2D or 3D information, or from which the desired information can be inferred. The images of these structures contain lines and/or curves whose orientation, lengths, and intersections characterize the overall network.Some examples exist of studies that have been done in the analysis of networks of natural structures. In, Sebok and Roemer determine the complexity of nerve structures in an EM formed slide. Here the number of nodes that exist in the image describes how dense nerve fibers are in a particular region of the skin. Hildith proposes a network structural analysis algorithm for the automatic classification of chromosome spreads (type, relative size and orientation).

Ultrastructure of periplasmic bodies in gram-negative bacteria

1990 ◽  
Vol 48 (3) ◽  
pp. 640-641
Author(s):  
Xie Nianming ◽  
Ding Shaoqing ◽  
Wang Luping ◽  
Yuan Zenglin ◽  
Zhan Guolai ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Campylobacter Jejuni ◽  
Proteus Mirabilis ◽  
Shigella Flexneri ◽  
Morphological Description ◽  
Gram Negative Bacteria ◽  
Periplasmic Space ◽  
Clostridium Tetani ◽  
Gram Negative ◽  
Brucella Canis

Perhaps the data about periplasmic enzymes are obtained through biochemical methods but lack of morphological description. We have proved the existence of periplasmic bodies by electron microscope and described their ultrastructures. We hope this report may draw the attention of biochemists and mrophologists to collaborate on researches in periplasmic enzymes or periplasmic bodies with each other.One or more independent bodies may be seen in the periplasmic space between outer and inner membranes of Gram-negative bacteria, which we called periplasmic bodies. The periplasmic bodies have been found in seven species of bacteria at least, including the Pseudomonas aeroginosa. Shigella flexneri, Echerichia coli. Yersinia pestis, Campylobacter jejuni, Proteus mirabilis, Clostridium tetani. Vibrio cholerae and Brucella canis.

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