Correlation between light-scattering changes and the energy state of phosphorylating submitochondrial particles

Conformational basis of energy transduction in mitochondria

“…When steady state conditions are carefully avoided, and conformational synchrony of the repeating units obtains, then configuration can be taken as a direct measure of conformation [S] . Light scattering at 90' measures the NE to E-T or E to E-T configurational transitions in isolated beef heart mitochondria [4,5] and aggregated to orthodox configurational transition in adrenal cortex mitochondria [ 131 . These light scattering measurements of configurational changes are also accurate indices of conformational changes when conformational synchrony of repeating units is achieved by eliminating steady state conditions, i.e., conditions which lead to rapid turnover of the energized state.…”

“…By any of three methods of measuring conformational change described above, a correlation was found to obtain between the energy and the conformational state of the particle. A further critical test of the correlation was passed with the demonstration that the half-time of proton release was approximately equal to the turnover of the electron transfer components in mitochondria under coupling conditions [ 161. We have been able to establish a correlation between energy and conformational state not only in isolated mitochondria from various sources but also in mitochondria in situ and in submitochondrial particles such as ETPB [4,17] . On the basis of these multiple lines of evidence we consider the case for identifying the energy and conformational states of the mitochondrion as complete.…”

“…These changes can be followed either by electron microscopic examination [ 171 or by light scattering measurements [4]. The E-T configuration in ETPB takes the form of an invagination of the boundary membrane into the interior space.…”

Effects of Picloram on Mitochondrial Swelling and ATPase

“…Not only volume changes in mitochondria but also configurational changes in their inner membrane would affect light scattering properties of mitochondria. Harris et ale (12) reported that the light scattering technique was a convenient way of continuously monitoring configurational changes during the energy cycle of mitochondria and submitochondrial particles. Thus, changes in absorbance caused by picloram in this study may reflect changes in both volume and configuration of mitochondria.…”

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“…Coupled submitochondrial particles such as ETPB clearly show configurational changes when exposed to energizing conditions in presence of inorganic phosphate. These changes can be followed either by electron microscopic examination [ 171 or by light scattering measurements [4]. The E-T configuration in ETPB takes the form of an invagination of the boundary membrane into the interior space.…”