Carborane-containing liquid crystals: synthesis and structural, conformational, thermal, and spectroscopic characterization of diheptyl and diheptynyl derivatives of p-carboranes.

Molecular and electronic structures for four p-carborane derivatives were studied in the context of their liquid crystalline properties. Thus molecular and crystal structures of diheptyl and diheptynyl derivatives of 10- and 12-vertex bi-p-carboranes were determined by X-ray crystallography and compared to the results of ab initio calculations at the HF/6-31G level of theory. Experimentally observed significant positional disorder of one of the substituents in the 10-vertex derivatives, 2[2]a and 2[2]b, was related to conformational properties of the alkyl-carborane bond.

The tertiary structure of full-length bovine adrenodoxin suggests functional dimers.

The three-dimensional X-ray crystal structure of full-length oxidized bovine adrenodoxin (Adx) has been determined at 2.5 A resolution by molecular replacement using a structure of a truncated form as a starting model. Crystals of Adx belong to a primitive monoclinic space group P2(1) with four Adx molecules in an asymmetric unit.

Conformational changes in the crystal structure of rat glutathione transferase M1-1 with global substitution of 3-fluorotyrosine for tyrosine.

The structure of the tetradeca-(3-fluorotyrosyl) M1-1 GSH transferase (3-FTyr GSH transferase), a protein in which tyrosine residues are globally substituted by 3-fluorotyrosines has been determined at 2.2 A resolution. This variant was produced to study the effect on the enzymatic mechanism and the structure was undertaken to assess how the presence of the 3-fluorotyrosyl residue influences the protein conformation and hence its function.

The abdominal muscles and vertebral stability.

It has been suggested that the muscles of the anterolateral abdominal wall increase the stability of the lumbar region of the vertebral column by tensing the thoracolumbar fascia and by raising intra-abdominal pressure. In this report these new mechanisms are reviewed and their contribution to vertebral stability assessed. The thoracolumbar fascia consists of two principal layers of dense fibrous tissue that attach the abdominal muscles to the vertebral column.