Tetramer, structure

Stein, M., Sauer, J., 1997, Formic Acid Tetramers Structure Isomers in the Gas Phase , Chem. Phys. Lett., 267,... 

Fig. 3. CD spectra of DIMS with flanking G-rich motifs. A spectrum with characteristic positive peaks in the range of 252-262 nm is typical of a parallel G-4 tetramer structure and is observed for DIMS9052, DIMS9054, DIMS9058, and DIMS9059 but not for DIMS9051. Two reference CD spectra are shown by thin lines parallel G4-tetramer formed by DIMS0400— thin black line random-coiled DIMS9011— thin grey line and indicated in the legend as tetramer and random, respectively.

The quantitative CD spectra analysis showed highest values of parallel G4-tetramer structure for compounds D1MS9054, D1MS9058, and D1MS9059 that perform best in the induction of IFNs, whereas compound D1MS9052 which shows a low parallel G4-tetramer value is able to induce intermediate levels of IFNa but not 1FN(3 or IFNy (Table 2). 

Eormula SbFs MW 216.74 hnear polymeric chains in hquid state and cychc tetramer structures in sohd phase associated with E bridging atoms. Such E bridges exist even in the gas phase (Passmore, J. 1985. J Chem. Soc. Dalton Trans., p. 9)... 

Tetramer. Structure resulting from the association of four subunits. 

Fig. 1 The structure of a-LTX. (a) Schematic of a-LTX processing in the venom gland, (b) Primary and domain structure. The numbered boxes, ankyrin repeats (ARs). Grey, imperfect repeats C, conserved cysteines residues in the N-terminal domain open arrowhead, insert in the mutant a-LTXN4C. Protein domains identified from the 3D structure (Orlova et al. 2000) are delimited below, (c) 3D reconstructions of the a-LTX monomer, dimer and tetramer, viewed from the top and side. The monomer has been computationally extracted from the experimentally determined tetramer structure. Left-most image, a scheme of the monomer, with the domains designated by different shades of grey. Filled arrowhead, strong association of the head domains in the dimer.

In another report, a microchip was interfaced to MS for the detection of the tetrameric plasma protein (transthyretin) which was involved in the transport of thyroxine. Screening of small molecules, including the natural ligand, thyroxine, that could stabilize the tetramer structure was carried out [779]. 

The aromatic nature of the tetraanionic layers of 58 was established by the shield-ing/deshielding effects found in the system. Ring currents cause enhanced shielding inside the tetramer core and thus some of the lithium cations are shifted to —14.5 ppm. In addition, the substituent groups of the two inner layers that extend to the sides of the tetramer structure are deshielded relative to analogous nuclei in the two outer layers. 

Waisman, D. M. (1995). Annexin II tetramer structure and function. Mol. Cell Biochem. 149-150, 301-322. 

Figure 1 shows Rh and Td tetramer structures examined using ADF. The interatomic distances, rji, ri2 and r were optimized for the AM and AE tetramers and the results are summarized in Table I (a). By looking at the bonding energy (B.E.) we can see that AM tetramers take up the 2-D... 

FIGURE 4. Proposed tetramer structure for humic acid. 

Rhodium(VI) and iridium(VI) occur only in black RhFg and yellow IrFg, formed by heating the metals with F2 under pressure and quenching the volatile products. Both RhFg and IrFg are octahedral monomers. The pentafluorides are made by direct combination of the elements (equation 22.100) or by reduction of MFg, and are moisture-sensitive (reaction 22.101) and very reactive. They are tetramers, structurally analogous to NbFs (22.5). 

Platinum(V) fluoride is a tetramer (structurally like 22.5) PtFg is a red solid and has a molecular structure consisting of octahedral molecules neutron powder diffraction data confirm little deviation from an ideal octahedral structure. The hexafluoride is a very powerful oxidizing agent (equation 22.127, and see Section 5.16) and attacks glass. The oxidizing power of the second row rZ-block hexafluorides... 

Ru(CO) and RhCl porphyrins with a meso-(p-pyridyl) substituent give rise to the formation of macrocyclic tetramers 40 and 41, respectively. The Ru tetramer structures were converted by an excess amount (103-fold) of pyridine into monomers. The Soret band sharpened during the change, showing the effect of excitonic interactions between the cofacially arranged porphyrins [71,72]. 

The experimental data could be accounted for by a puckered cyclic tetramer of S4 symmetry, although other cyclic tetramer structures of lower syimnetry could not definitely be excluded. 

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