ChemInform Abstract: Chemical Construction and Structural Permutation of Neurotoxic Natural Product, Antillatoxin: Importance of the Three-Dimensional Structure of the Bulky Side Chain

ChemInform ◽  
2014 ◽  
Vol 45 (29) ◽  
pp. no-no
Author(s):  
Masayuki Inoue
Reproduction ◽  
2004 ◽  
Vol 127 (4) ◽  
pp. 417-422 ◽  
Author(s):  
Tanya Hoodbhoy ◽  
Jurrien Dean

The zona pellucida surrounding the egg and pre-implantation embryo is required for in vivo fertility and early development. Explanatory models of sperm–egg recognition need to take into account the ability of sperm to bind to ovulated eggs, but not to two-cell embryos. For the last two decades, investigators have sought to identify an individual protein or carbohydrate side chain as the ‘sperm receptor’. However, recent genetic data in mice are more consistent with the three-dimensional structure of the zona pellucida, rather than a single protein (or carbohydrate), determining sperm binding. The mouse and human zonae pellucidae contain three glycoproteins (ZP1, ZP2, ZP3) and, following fertilization, ZP2 is proteolytically cleaved. The replacement of endogenous mouse proteins with human ZP2, ZP3 or both does not alter taxon specificity of sperm binding or prevent fertility. Surprisingly, human ZP2 is not cleaved following fertilization and intact ZP2 correlates with persistent sperm binding to two-cell embryos. Taken together, these data support a model in which the cleavage status of ZP2 modulates the three-dimensional structure of the zona pellucida and determines whether sperm bind (uncleaved) or do not (cleaved).


2014 ◽  
Vol 70 (9) ◽  
pp. o938-o939
Author(s):  
Shaaban K. Mohamed ◽  
Mehmet Akkurt ◽  
Joel T. Mague ◽  
Eman A. Ahmed ◽  
Mustafa R. Albayati

The title compound, C14H15N3O4, is nearly planar, the dihedral angle between the planes of the phenyl and pyrazolidine rings being 1.13 (7) Å, and that between the plane of the pyrazolidine ring and the mean plane of the side chain [C—N—C–C(=O)—O; r.m.s. deviation = 0.024 Å] being 2.52 (7)°. This is due in large part to the presence of the intramolecular N—H...O and C—H...O hydrogen bonds. In the crystal, pairwise N—H...O hydrogen bonds form inversion dimers, which are further associated into layers, lying very close to plane (-120),viapairwise C—H...O hydrogen bonds. The layers are then weakly connected through C—H...O hydrogen bonds, forming a three-dimensional structure.


Author(s):  
N. H. Olson ◽  
T. S. Baker ◽  
Wu Bo Mu ◽  
J. E. Johnson ◽  
D. A. Hendry

Nudaurelia capensis β virus (NβV) is an RNA virus of the South African Pine Emperor moth, Nudaurelia cytherea capensis (Lepidoptera: Saturniidae). The NβV capsid is a T = 4 icosahedron that contains 60T = 240 subunits of the coat protein (Mr = 61,000). A three-dimensional reconstruction of the NβV capsid was previously computed from visions embedded in negative stain suspended over holes in a carbon film. We have re-examined the three-dimensional structure of NβV, using cryo-microscopy to examine the native, unstained structure of the virion and to provide a initial phasing model for high-resolution x-ray crystallographic studiesNβV was purified and prepared for cryo-microscopy as described. Micrographs were recorded ∼1 - 2 μm underfocus at a magnification of 49,000X with a total electron dose of about 1800 e-/nm2.


Author(s):  
David A. Agard ◽  
Yasushi Hiraoka ◽  
John W. Sedat

In an effort to understand the complex relationship between structure and biological function within the nucleus, we have embarked on a program to examine the three-dimensional structure and organization of Drosophila melanogaster embryonic chromosomes. Our overall goal is to determine how DNA and proteins are organized into complex and highly dynamic structures (chromosomes) and how these chromosomes are arranged in three dimensional space within the cell nucleus. Futher, we hope to be able to correlate structual data with such fundamental biological properties as stage in the mitotic cell cycle, developmental state and transcription at specific gene loci.Towards this end, we have been developing methodologies for the three-dimensional analysis of non-crystalline biological specimens using optical and electron microscopy. We feel that the combination of these two complementary techniques allows an unprecedented look at the structural organization of cellular components ranging in size from 100A to 100 microns.


Author(s):  
José L. Carrascosa ◽  
José M. Valpuesta ◽  
Hisao Fujisawa

The head to tail connector of bacteriophages plays a fundamental role in the assembly of viral heads and DNA packaging. In spite of the absence of sequence homology, the structure of connectors from different viruses (T4, Ø29, T3, P22, etc) share common morphological features, that are most clearly revealed in their three-dimensional structure. We have studied the three-dimensional reconstruction of the connector protein from phage T3 (gp 8) from tilted view of two dimensional crystals obtained from this protein after cloning and purification.DNA sequences including gene 8 from phage T3 were cloned, into Bam Hl-Eco Rl sites down stream of lambda promotor PL, in the expression vector pNT45 under the control of cI857. E R204 (pNT89) cells were incubated at 42°C for 2h, harvested and resuspended in 20 mM Tris HC1 (pH 7.4), 7mM 2 mercaptoethanol, ImM EDTA. The cells were lysed by freezing and thawing in the presence of lysozyme (lmg/ml) and ligthly sonicated. The low speed supernatant was precipitated by ammonium sulfate (60% saturated) and dissolved in the original buffer to be subjected to gel nitration through Sepharose 6B, followed by phosphocellulose colum (Pll) and DEAE cellulose colum (DE52). Purified gp8 appeared at 0.3M NaCl and formed crystals when its concentration increased above 1.5 mg/ml.


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