Template complex zonotopes for stability and invariant verification

Author(s):  
Arvind Adimoolam ◽  
Thao Dang
Keyword(s):  
1970 ◽  
Vol 117 (3) ◽  
pp. 623-631 ◽  
Author(s):  
Volker Neuhoff ◽  
Wolf-Bernhard Schill ◽  
Hans Sternbach

By using micro disc electrophoresis and micro-diffusion techniques, the interaction of pure DNA-dependent RNA polymerase (EC 2.7.7.6) from Escherichia coli with the template, the substrates and the inhibitors heparin and rifampicin was investigated. The following findings were obtained: (1) heparin converts the 24S and 18S particles of the polymerase into the 13S form; (2) heparin inhibits RNA synthesis by dissociating the enzyme–template complex; (3) rifampicin does not affect the attachment of heparin to the enzyme; (4) the substrates ATP and UTP are bound by enzyme loaded with rifampicin; (5) rifampicin is bound by an enzyme–template complex to the same extent as by an RNA-synthesizing enzyme–template complex. From this it is concluded that the mechanism of the inhibition of RNA synthesis by rifampicin is radically different from that by heparin. As a working hypothesis to explain the inhibitory mechanism of rifampicin, it is assumed that it becomes very firmly attached to a position close to the synthesizing site and only blocks this when no synthesis is in progress.


2018 ◽  
Vol 41 (3-4) ◽  
pp. 129-133 ◽  
Author(s):  
De-Gui Shu ◽  
Wen-Yu Chen

Abstract Here, a new indium (In)-based coordination polymer [In(hip)](DMF)2(H2O)3 (1, DMF=N,N-dimethylformamide) was successfully prepared by a solvothermal reaction of In(NO3)3·6H2O and 5-hydroxyisophthalic acid (H3hip) in a mixed solvent of DMF and H2O with the presence of NaCl as a template. Complex 1 was characterized by elemental analysis (EA), single-crystal X-ray crystallography, and powder X-ray diffraction (PXRD), and the results reveal that complex 1 shows a two-dimensional (2D) grid-like network with considerable solvent accessible volume that was generated from the packing of the 2D layers via the AB pattern. Furthermore, complex 1 could be downsized into nanoscale particles with the aid of polyvinylpyrrolidone (PVP). In addition, the anticancer activities of 1 and the nanoscale 1 were probed via the 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay.


Author(s):  
Yi Zhang ◽  
Zheng Ji Li

Support system for traditional template complex operation, high construction costs, the safety factor is low, and more can not be achieved as early as demolition, parts and more status quo. Successful development of high efficiency-low consumption combined formwork system can replace the traditional template scaffold support system, this system has a standardized, one-button, early split type, reduce labor intensity and improve working efficiency, save construction costs.


2020 ◽  
Author(s):  
R Venkat Kalyana Sundaram ◽  
Huaizhou Jin ◽  
Feng Li ◽  
Tong Shu ◽  
Jeff Coleman ◽  
...  

ABSTRACTSynaptic vesicle fusion is mediated by membrane-bridging complexes formed by SNARE proteins - VAMP2 on the vesicle and Syntaxin-1/SNAP25 on the pre-synaptic membrane. Accumulating evidence suggest that chaperones Munc18-1 and Munc13-1 co-operatively catalyze SNARE assembly via an intermediate ‘template’ complex containing Syntaxin-1 and VAMP2. How SNAP25 is chaperoned into this nascent complex remains a mystery. Here we report that Munc13-1 recruits SNAP25 to initiate the ternary SNARE complex assembly by direct binding, as judged by bulk FRET spectroscopy and single-molecule optical tweezer studies. Detailed structure-function analyses show that the binding is mediated by the Munc13-1 MUN domain and is specific for the SNAP25 ‘linker’ region that connects the two SNARE motifs. Consequently, freely diffusing SNAP25 molecules on phospholipid bilayers are concentrated and presumably bound in ~1:1 stoichiometry by the self-assembled Munc13-1 nanoclusters. Our data suggests that Munc13-1’s capacity to bind all three synaptic SNARE proteins likely underlie its chaperone function.


eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Junyi Jiao ◽  
Mengze He ◽  
Sarah A Port ◽  
Richard W Baker ◽  
Yonggang Xu ◽  
...  

Sec1/Munc18-family (SM) proteins are required for SNARE-mediated membrane fusion, but their mechanism(s) of action remain controversial. Using single-molecule force spectroscopy, we found that the SM protein Munc18-1 catalyzes step-wise zippering of three synaptic SNAREs (syntaxin, VAMP2, and SNAP-25) into a four-helix bundle. Catalysis requires formation of an intermediate template complex in which Munc18-1 juxtaposes the N-terminal regions of the SNARE motifs of syntaxin and VAMP2, while keeping their C-terminal regions separated. SNAP-25 binds the templated SNAREs to induce full SNARE zippering. Munc18-1 mutations modulate the stability of the template complex in a manner consistent with their effects on membrane fusion, indicating that chaperoned SNARE assembly is essential for exocytosis. Two other SM proteins, Munc18-3 and Vps33, similarly chaperone SNARE assembly via a template complex, suggesting that SM protein mechanism is conserved.


eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Travis J Eisemann ◽  
Frederick Allen ◽  
Kelly Lau ◽  
Gregory R Shimamura ◽  
Philip D Jeffrey ◽  
...  

Fusion of intracellular trafficking vesicles is mediated by the assembly of SNARE proteins into membrane-bridging complexes. SNARE-mediated membrane fusion requires Sec1/Munc18-family (SM) proteins, SNARE chaperones that can function as templates to catalyze SNARE complex assembly. Paradoxically, the SM protein Munc18-1 traps the Qa-SNARE protein syntaxin-1 in an autoinhibited closed conformation. Here we present the structure of a second SM–Qa-SNARE complex, Vps45–Tlg2. Strikingly, Vps45 holds Tlg2 in an open conformation, with its SNARE motif disengaged from its Habc domain and its linker region unfolded. The domain 3a helical hairpin of Vps45 is unfurled, exposing the presumptive R-SNARE binding site to allow template complex formation. Although Tlg2 has a pronounced tendency to form homo-tetramers, Vps45 can rescue Tlg2 tetramers into stoichiometric Vps45–Tlg2 complexes. Our findings demonstrate that SM proteins can engage Qa-SNAREs using at least two different modes, one in which the SNARE is closed and one in which it is open.


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