How alpha-crystallin prevents the aggregation of insulin.
Using steady-state, polarized, and phase-modulation fluorometry, the dithiothreitol-induced denaturation of insulin and formation of its complex with alpha-crystallin in solution were studied. Prevention of the aggregation of insulin by alpha-crystallin is due to formation of chaperone complexes, i.e. interaction of chains of the denatured insulin with alpha-crystallin. The conformational changes in alpha-crystallin that occur during complex formation are rather small. It is unlikely that N-termini are directly involved in the complex formation. The 8-anilino-1-naphthalenesulfonate (ANS) is not sensitive to the complex formation. ANS emits mainly from alpha-crystallin monomers, dimers, and tetramers, but not from oligomers or aggregates. The possibility of highly sensitive detection of aggregates by light scattering using a spectrofluorometer with crossed monochromators is demonstrated.
Vekshin
N L
NL
Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia. nvekshin@rambler.ru.
D000817:Anilino Naphthalenesulfonates / Q000737:chemistry; D000818:Animals; D002417:Cattle; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry; D007328:Insulin / Q000737:chemistry*; D008027:Light; D011489:Protein Denaturation; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000737:chemistry; D014443:Tyrosine / Q000737:chemistry; D038201:alpha-Crystallins / Q000737:chemistry*
C515594:8-anilino-1-naphthalenesulfonic acid; D000817:Anilino Naphthalenesulfonates; D005456:Fluorescent Dyes; D007328:Insulin; D038201:alpha-Crystallins; D014443:Tyrosine; D014364:Tryptophan