2.4. Aggregation propensity
The aggregation propensity of MNEI and Y65R was assessed by
incubating protein aliquots in 100 mM ammonium acetate buffer,
pH 5.1 or in 100 mM phosphate buffer at pH 6.8. The protein samples,
all at a concentration of 0.5 mg ml1, were incubated at different
temperatures for times ranging from 2 to 24 h. At the time
indicated aliquots of 20 ll were withdrawn for the control, while
the remaining part of the sample was centrifuged at 13.000 rpm
for 3 min, to separate the supernatant from the pellet, which was
suspended in 100 ll of loading buffer. Identical volumes (20 ll)
of supernatant and precipitate were then loaded on the same gel,
to evaluate protein solubility and tendency to form sodium dodecyl
sulphate (SDS) resistant aggregates. SDS polyacrylamide gel
electrophoresis (PAGE) was performed according to the Laemmli
protocol using 15% polyacrylamide gels. Gels were
stained with Coomassie Brilliant Blue R-250.