Optical rotatory dispersion subunits

The physical and chemical properties of the AChR have been elucidated. Optical rotatory dispersion measurements indicate that the receptor consists of about 34% helix and 28-30% P-sheet structure—a high proportion of ordered secondary structure. Some carbohydrates are part of the molecule. The DNA encoding the receptor has been cloned and sequenced, revealing the complete amino acid sequence of the subunits. 

Subunits of myosin. Hanafusa (97.,98) found that isolated rabbit myosin and HMM underwent denaturation when cooled to temperatures ranging from -10° to -196°C followed by immediate thawing. Denaturation was measured by an increase in viscosity, change in absorbance at 278 nm and change in the optical rotatory dispersion coefficients, a0 and b0, in the Moffit-Young equation. The absolute value of b0 decreased while that of a0 increased with a decrease in the freezing temperature. 

In Figure 5 the optical rotatory dispersions and CD spectra of some frans-disubstituted cyclopropane hydrocarbons are displayed Compound 1 has C2 symmetry and with respect to the cyclopropane subunit also 114 and 115 have a local C2 symmetry. Trans-1,2-dimethylcyclopropane (1) exhibits a continuous CD rising to a positive Cotton effect... 

The Danielli-Davson model has been modified by Wallach and Zahler (1966) who demonstrated by optical rotatory dispersion and circular dichroism techniques that a substantial amount of membrane protein exists in a helical conformation as opposed to random coil It is envisioned that hydrophilic portions of membrane protein are located on both sides of the membrane and are connected by hydrophobic microtubules. Lenard and Singer (1966) also advanced similar views and suggested that subunits could result from this model which, when assembled in two dimensions, could form a membrane. 

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