Kinetics of thermal aggregation of glycogen phosphorylase b from rabbit skeletal muscle: Mechanism of protective action of α‐crystallin

Abstract

The kinetics of thermal aggregation of glycogen phosphorylase b (Phb) from rabbit skeletal muscle have been studied by dynamic light scattering (0.08M Hepes, pH 6.8, containing 0.1M NaCl; 48 degrees C). The hydrodynamic radius of the start aggregates determined from the initial linear parts of the dependences of the hydrodynamic radius (R(h)) on time was found to be 16.7 +/- 1.0 nm. At rather high values of time, the R(h) value for the protein aggregates becomes proportional to t(1/1.8) = t(0.56) suggesting that the aggregation process proceeds in the regime of diffusion-limited cluster-cluster aggregation. In the presence of alpha-crystallin, a protein possessing the chaperone-like activity, the process of protein aggregation switches to the regime of reaction-limited cluster-cluster aggregation as indicated by the exponential dependence of the R(h) value on time. It was shown that the addition of alpha-crystallin raises the rate of thermal inactivation of Phb. These data in combination with the results of the study of interaction of Phb with alpha-crystallin by analytical ultracentrifugation suggest that alpha-crystallin interacts with the intermediates of unfolding of the Phb molecule.

Effect of 2‐hydroxypropyl‐β‐cyclodextrin on thermal stability and aggregation of glycogen phosphorylase b from rabbit skeletal muscle

“…The value of parameter d f was found to be 1.79 6 0.01. This result agrees with the data obtained in our previous works 23,24 and indicates that aggregation proceeds in the regime diffusion-limited cluster-cluster aggregation (DLCA). 25,26 Realization of this regime of aggregation means that each collision of the interacting particles results in their sticking.…”

Arginine controls heat‐induced cluster–cluster aggregation of lysozyme at around the isoelectric point

“…[38][39][40] In fact, the addition of Arg resulted in the formation of denser aggregates than those in the absence of solution additives (see Figure 4). It is worth mentioning that a-crystallin 33,35,37 and GroEL 53 change the regime of protein aggregation from DLCA to RLCA. Both a-crystallin 56,57 and GroEL 58,59 prevent protein aggregation by stabilization of denatured protein via complexation.…”

Mechanism of suppression of dithiothreitol-induced aggregation of bovine α-lactalbumin by α-crystallin

“…com) as described in our previous works where DLS was used for the study of the kinetics of thermal aggregation of proteins [1,4,5,24]. An HeNe laser (Coherent, USA, Model 31-2082, 632.8 nm, 10 mW) was used as the light source.…”

“…The hydrodynamic radius of the start aggregates was tens of nanometers. The start aggregate formation was revealed in the process of thermal aggregation of the following model substrates: β L -crystallin from bovine lens [1], glyceraldehyde-3-phosphate dehydrogenase and glycogen phosphorylase b from rabbit skeletal muscle [2][3][4][5][6], aspartate aminotransferase from pig heart mitochondria [7] and tobacco mosaic virus coat protein [8].…”