DIFFICULTIES WITH OPEN STRUCTURES

1972 ◽  
Vol 33 (C3) ◽  
pp. C3-209-C3-212 ◽  
Author(s):  
J. M. ZIMAN
Keyword(s):  
Open Structures

Exact "Absorbing" Conditions for Modeling of Transients in Open Structures

2001 ◽  
Vol 55 (6-7) ◽  
pp. 11 ◽  
Author(s):  
Yurii Konstantinovich Sirenko ◽  
Andrei Olegovich Perov ◽  
E. Yaldiz
Keyword(s):  
Open Structures

Synthetic Strategies for Hollow Particles with Open Holes on Their Surfaces

2021 ◽  
Author(s):  
Hua Zou ◽  
Ke Shang
Keyword(s):  
Hollow Particles ◽  
Single Hole ◽  
Open Structures

Hollow particles with open holes on their surfaces, which refer to hollow micro/nano spheres with open structures such as single hole or multi-holes on their surface, have attracted increasing interest...

scholarly journals 1. On the Computation of the Strengths of the Parts of Skeleton or Open Structures

1872 ◽  
Vol 7 ◽  
pp. 575-576
Author(s):  
Edward Sang
Keyword(s):  
The Other ◽  
Open Structures ◽  
First Time ◽  
General Configuration

The first part of the paper is devoted to the computation of the strengths of the parts of a structure destined to resist given strains, taking into account, along with those strains, the unknown weights of the parts. The results obtained by this process necessarily give the best possible arrangement of the strengths, since, if any one part were made weaker, the whole structure would be weakened; or, if a part were made stronger, the unnecessary weight thus thrown upon the other parts would also go to weaken the fabric. It is believed that this investigation has now been given for the first time.It was pointed out that this method enables us to determine the utmost limit of magnitude of a structure having a given general configuration.

Nucleosome structure

1978 ◽  
Vol 283 (997) ◽  
pp. 241-258 ◽  
Keyword(s):  
Dynamic Structure ◽  
Histone H2a ◽  
Electron Microscopic ◽  
Base Pairs ◽  
Compact Structure ◽  
Nucleosome Structure ◽  
Dna Base ◽  
Open Structures ◽  
Dna 2 ◽  
Necessary And Sufficient

Electron microscopic and biochemical results are presented supporting the following conclusions: (1) Two molecules of each histone H2A, H2B, H3 and H4 are necessary and sufficient to form a nucleosome with a diameter of 12.5± 1 nm and containing about 200 base pairs of DNA. (2) H3 plus H4 alone can compact 129 ± 8 DNA base pairs into a sub-nucleosomal particle with a diameter of 8 ± 1 nm. In such a particle the DNA duplex is under a constraint equivalent to negative superhelicity. (3) Chromatin should be viewed as a dynamic structure, oscillating between a compact structure (the nucleosome) and more open structures, depending on the environmental conditions.

scholarly journals The role of membrane destabilisation and protein dynamics in BAM catalysed OMP folding

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Paul White ◽  
Samuel F. Haysom ◽  
Matthew G. Iadanza ◽  
Anna J. Higgins ◽  
Jonathan M. Machin ◽  
...  
Keyword(s):  
Outer Membrane Proteins ◽  
Antibody Fragment ◽  
Membrane Disruption ◽  
Gram Negative Bacteria ◽  
Wild Type ◽  
Lipid Dynamics ◽  
Open Structures

AbstractThe folding of β-barrel outer membrane proteins (OMPs) in Gram-negative bacteria is catalysed by the β-barrel assembly machinery (BAM). How lateral opening in the β-barrel of the major subunit BamA assists in OMP folding, and the contribution of membrane disruption to BAM catalysis remain unresolved. Here, we use an anti-BamA monoclonal antibody fragment (Fab1) and two disulphide-crosslinked BAM variants (lid-locked (LL), and POTRA-5-locked (P5L)) to dissect these roles. Despite being lethal in vivo, we show that all complexes catalyse folding in vitro, albeit less efficiently than wild-type BAM. CryoEM reveals that while Fab1 and BAM-P5L trap an open-barrel state, BAM-LL contains a mixture of closed and contorted, partially-open structures. Finally, all three complexes globally destabilise the lipid bilayer, while BamA does not, revealing that the BAM lipoproteins are required for this function. Together the results provide insights into the role of BAM structure and lipid dynamics in OMP folding.

scholarly journals Engineered occluded apo-intermediate of LacY

2018 ◽  
Vol 115 (50) ◽  
pp. 12716-12721 ◽  
Author(s):  
Irina Smirnova ◽  
Vladimir Kasho ◽  
H. Ronald Kaback
Keyword(s):  
Binding Site ◽  
Lactose Permease ◽  
Binding Studies ◽  
X Ray Crystallography ◽  
Sugar Binding ◽  
Transport Cycle ◽  
Open Structures ◽  
Unrestricted Access ◽  
Tight Association ◽  
Alternating Access

The lactose permease of Escherichia coli (LacY) utilizes an alternating access symport mechanism with multiple conformational intermediates, but only inward (cytoplasmic)- or outward (periplasmic)-open structures have been characterized by X-ray crystallography. It is demonstrated here with sugar-binding studies that cross-linking paired-Cys replacements across the closed cytoplasmic cavity stabilize an occluded conformer with an inaccessible sugar-binding site. In addition, a nanobody (Nb) that stabilizes a periplasmic-open conformer with an easily accessible sugar-binding site in WT LacY fails to cause the cytoplasmic cross-linked mutants to become accessible to galactoside, showing that the periplasmic cavity is closed. These results are consistent with tight association of the periplasmic ends in two pairs of helices containing clusters of small residues in the packing interface between N- and C-terminal six-helix bundles of the symporter. However, after reduction of the disulfide bond, the Nb markedly increases the rate of galactoside binding, indicating unrestricted access to the Nb epitope and the galactoside-binding site from the periplasm. The findings indicate that the cross-linked cytoplasmic double-Cys mutants resemble an occluded apo-intermediate in the transport cycle.

Boronyl as a terminal ligand in boron oxide clusters: hexagonal ring C2vB6O4and ethylene-like D2hB6O4−/2−

2015 ◽  
Vol 17 (30) ◽  
pp. 19929-19935 ◽  
Author(s):  
Wei Wang ◽  
Qiang Chen ◽  
Ying-Jin Wang ◽  
Hui Bai ◽  
Ting-Ting Gao ◽  
...  
Keyword(s):  
Boron Oxide ◽  
Terminal Ligand ◽  
Hexagonal Ring ◽  
Open Structures

Planar boron boronyl B6O40/−/2−clusters are predicted. B6O4is an inorganic analogue of benzene, whereas B6O4−/2−are ethylene-like with open structures.

1. On Cases of Instability in Open Structures

1888 ◽  
Vol 14 ◽  
pp. 106-106
Author(s):  
E. Sang
Keyword(s):  
Linear Structures ◽  
Symmetric Structure ◽  
Linear Resistance ◽  
Open Structures ◽  
Extensive Class ◽  
The Subject ◽  
The Stability ◽  
Special Case

AbstractIn the course of some remarks on the design proposed for the Forth Bridge, the author of this paper had enunciated the remarkable theorem, that any symmetric structure built on a rectangular base, and depending on linear resistance alone, is necessarily unstable. The proof of it, given in the eleventh volume of the Transactions of the Royal Scottish Society of Arts, is derived from considerations affecting the special case; but this theorem is only one of an extensive class, and therefore the subject of instability among linear structures in general is here taken up.In the case of regular or semi-regular arrangements, having the corners of an upper supported from the corners of an under polygon, it is shown that when the figures are of odd numbers the structures are stable, while those with even numbers are unstable ; unless indeed the polygons be placed conformably, in which case the stability extends to both classes.

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