Trimer molecule

The hemagglutinin trimer molecule is 135 A long (from membrane to tip) and varies in cross-section between 15 A and 40 A. It is thus an unusually... 

Dialkyl zinc compounds form phosphine complexes of formula RZnP(SiMe3)2 on addition of one equivalent of bis(trimethylsilyl)phosphine. Solution and solid-state studies showed that the complexes are dimeric or trimeric in solution or the solid state. Bis(trimethylsilyl)phosphido-methylzinc crystallizes as a trimeric molecule with a Zn3P3 core in the twist-boat conformation. Bis(trimethylsilyl)phosphido- -butylzinc, shows a similar central Zn3P3 fragment. The sterically more demanding trimethylsilylmethyl substituent forms a dimeric species of bis(trimethylsilyl) phosphido-trimethylsilylmethylzinc. Solution studies of bis(trimethylsilyl)phosphido- .vo-propyl-zinc demonstrate a temperature-dependent equilibrium of the dimeric and trimeric species and the crystalline state contains a 1 1 mixture of these two oligomers. A monomeric bis(trimethyl-silyl)phosphido-tris(trimethylsilyl)methylzinc has also been synthesized.313... 

In case a polymer sample weighs W grams and contains n, monomer molecules each Molecular weight Mls n2 dimer molecules of Molecular weight M2, n3 trimer molecules of Molecular weight M3.ni i-mer... 

For most collagens, the folding of the triple helical domain proceeds from the carboxyl end toward the amino end of the trimeric molecule in a zipper-like fashion with a rate that is limited by cis—trans isomerization of peptidyl prolyl bonds." The fast propagation of the triple helix formation is followed by a slower folding... 

The conformational properties of trimer molecules modeling PVDB (S 100) and PVDF are analyzed by the molecular mechanics method of Boyd and Kesner [J. Chem. Phys. 1980, 72, 21791, which takes into account both steric and electrostatic energy. Total conformational energies are used to calculate a set of intramolecular interaction energies that, by means of the RIS model, allowed estimation of the characteristic ratios and dipole moment ratios of PVDB and PVDF under unperturbed conditions. 

On addition of PrOH to the crystals it is possible first to obtain very concentrated solutions, from which then commences the crystallization of poorly soluble tetrameric form (Fig. 6.2). It can be supposed that the trimer molecule coordinates an additional alcohol molecule along the sixth coordinate of the central aluminum metal in solution and then forms with the aid of hydrogen bonding the intermediates, which transform subsequently into tetrameric molecules already containing the hcxacoordi nated central A1 atom. The incomplete coordination polyhedron ofthe A1 atom is thus responsible for the thermodynamic instability ofthe phase, where it is present [1642],... 

The same picture observed for the samples of [Fe(OPr )3]n is caused by the presence of aggregates with different molecular complexity (h = 2, 3, and °°). The former 2 kinds are present in the overcooled brown melt the large reddish-brown crystals formed from diluted solutions in alcohol consist of trimeric molecules (m. 117°C). The yellow powder obtained as residue after extraction ofthe more soluble forms with alcohol is a polymer (m. 157°Q. On action of benzene its color darkens, the molecular complexity turns to be 3, and the melting point varies in the 120 to 150°C interval [1647]. The scheme ofthe occurring transformations is summarized in the Fig. 12.3. 

Only poorly diffracting crystals of the monoclinic polymorph of Au 3 (MeN = COMe)3 could be obtained [41]. These appear to contain a stacking fault and may have been twinned. The arrangement of these gold atoms within the unit cell is shown in Fig. 20. There are two crystallographically different prismatic stacks each contains just three of the trinuclear molecules. The average out-of plane Au Au distance in these stacks is 3.28(3) A. While there is stacking of the trimeric molecules in this polymorph, these stacks are... 

The copper-containing nitrite reductase from A. cycloclastes may also have evolved from this ancestral oxidase. Nitrite reductase is a two-domain protein that functions as a trimeric molecule. During its evolution from the ancestral copper oxidase, a gene inversion must have occurred, so that domain 2 of the ancestral oxidase is now domain 1 of nitrite reductase. Domain 1 of the ancestral oxidase lost its type-1 copper but has become domain 2 in nitrite reductase after the gene inversion. 

At the ends of the polymer chains and at the ends of the short oligomer units (see for example the trimer molecule of Table 1) a bond defect structure is expected. For the acetylene structure of the polymer chain this is a carbene —C— with two free valence electrons and in the case of the butatriene structure this is a radical carbon atom —C= with one free valence electron. In both rases there is a reactive chain end, which allows reaction of the chain with the neighbouring monomer molecules. These reactive structures and a possible nonreactive structure are listed in Table 1 as examples of the trimer molecules. 

Table 2. Symbols, spin multiplicities, structures and notations. The simplified structures of the reaction intermediates and of the final stable products are shown schematically by example of the trimer molecule...

By analogy to the optical absorptions A to E (see Fig. 5) the kinetical generation sequence of the diradical oligomers I to III obtained upon UV-irradiation of the monomer crystals is shown in Fig. 11 Only the ESR line I is formed without any delay. The curves are calculated using the kinetic model described below. In this model the ESR line I corresponds to the DR dimer molecule, II to the DR trimer molecule, etc. 

The molecular species produced on vaporization of lithium fluoride have been studied by many investigators during the last ten years. The occurrence of dimer and trimer molecules in addition to the monomer has been established by use of mass spectrometric (4, 7, 8), torsion effusion (3, 6), molecular beam (9, 1 ) and transpiration (11) methods. To evaluate A pH (LlF, g) we have used a trial and error variation of and for the monomer, dimer and trimer in order to obtain reasonable agreement with the... 

The following diagrams illustrate the formulae (25.33) and (25.34) for a two-dimensional lattice with z = For a linear trimer molecule we have, in conformity with (25.33)... 

Because HA is a protein bound to viral membrane, multivalent ligands can interact with a single trimer or by spanning neighboring trimers. Molecules that can place multiple sialic acid residues in binding sites within a trimer might be expected to... 

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