Table 1.

Biochemical data for proteins subjected to sonication

				Native secondary structureb			Aggregate secondary structureb
Protein	Molecular weighta (kDa)	Number of disulfides	Number of free thiols	Alpha (%)	Beta (%)	Random (%)	Alpha (%)	Beta (%)	Random (%)	ThT increasec (fold)	CR shiftd (nm)
BSA	66.4	17	1	74	11	14	38	35	26	12	528
Myoglobin	17.0	0	0	66	17	16	48	28	23	2.2	543
Lysozyme	14.6	4	0	29	42	28	16	54	31	5.4	543
Tm0979	24.0	0	0	10	57	32	10	59	31	38	526
SOD	31.8	2	0	8	59	32	9	60	31	5.3	522
Hisactophilin	13.7	0	1	6	61	32	7	61	32	29	543

^a MW for native proteins, which are all monomers except for SOD and Tm0979, which are dimers. The pdb codes for the proteins are 1AO6 for human serum albumin (structure for BSA has not been reported), 1WLA for myoglobin, 1E8L for lysozyme, 1X9A for Tm0979, 1HCE for hisactophilin, and 1SOS for SOD.

^b Percent secondary structure was estimated on DICHROWEB using the CDSSTR method (Sreerama and Woody 2000; Lobley et al. 2002); beta = (β-strands + β-turns). Changes in β-structure for BSA, myoglobin, and lysozyme are predominantly due to augmented β-strand levels (>54, 73, and 92%, respectively).

^cThT increase was determined by dividing the fluorescence intensity at the maximum wavelength for the sonicated protein spectra by the fluorescence intensity of the native protein spectra at the same wavelength.

^dCR shift was determined by subtracting the native protein spectra from the sonicated protein spectra and determining the points of maximal spectral difference.