Untitled

Abstract

The kinetics of thermal aggregation of coat protein (CP) of tobacco mosaic virus (TMV) have been studied at 42 and 52 degrees C in a wide range of protein concentrations, [P]0. The kinetics of aggregation were followed by monitoring the increase in the apparent absorbance (A) at 320 nm. At 52 degrees C the kinetic curves may be approximated by the exponential law in the range of TMV CP concentrations from 0.02 to 0.30 mg/ml, the first order rate constant being linearly proportional to [P]0 (50 mM phosphate buffer, pH 8.0). The analogous picture was observed at 42 degrees C in the range of TMV CP concentrations from 0.01 to 0.04 mg/ml (100 mM phosphate buffer, pH 8.0). At higher TMV CP concentrations the time of half-conversion approaches a limiting value with increasing [P]0 and at sufficiently high protein concentrations the kinetic curves fall on a common curve in the coordinates [A/A(lim); t] (t is time and A(lim) is the limiting value of A at t --> infinity). According to a mechanism of aggregation of TMV CP proposed by the authors at rather low protein concentrations the rate of aggregation is limited by the stage of growth of aggregate, which proceeds as a reaction of the pseudo-first order, whereas at rather high protein concentrations the rate-limiting stage is the stage of protein molecule unfolding.

A change in the aggregation pathway of bovine serum albumin in the presence of arginine and its derivatives

“…The stage of protein unfolding proceeds very fast, and the rate-limiting stage of the overall process of aggregation is that of aggregation of unfolded protein molecules. The second order of aggregation with respect to protein was observed, for example, for thermal aggregation of bovine α-chymotrypsinogen A type II (20 mM sodium citrate, pH 5, at 52.5 °C 20 ), tobacco mosaic virus coat protein (50 mM phosphate buffer, pH 8.0, at 42 °C and 52 °C 45 ), firefly luciferase (25 mM Tricine, pH 7.5, at 42 °C 46 ) and apoglycogen phosphorylase b from rabbit skeletal muscles (0.08 M Hepes buffer, pH 6.8, containing 0.1 M NaCl and 5 mM DTT at 37 °C 47 ).…”

Quantification of Anti-Aggregation Activity of Chaperones: A Test-System Based on Dithiothreitol-Induced Aggregation of Bovine Serum Albumin

“…6B). Such a peculiarity of the aggregation kinetics indicates that DTT-induced aggregation of BSA proceeds by a mechanism of nucleation-dependent aggregation [76], [102]–[106]. However, in contrast to α-lactalbumin and insulin, nuclei formed in the course of DTT-induced aggregation of BSA are not capable of assembling into start aggregates.…”

Thermal disaggregation of type B yeast hexokinase by indole derivatives: A mechanistic study

“…Turbidity measurements were made at specified wavelengths, essentially as described earlier [28,29] to follow protein aggregation. A Cary-100 Bio VARIAN spectrophotometer was used and temperatures were controlled to within ±0.1 • C by a Cary temperature controller.…”