title: Thioflavin T-Silent Denaturation Intermediates Support the Main-Chain-Dominated Architecture of Amyloid Fibrils.
abstract: Ultrasonication is considered one of the most effective agitations for inducing the spontaneous formation of amyloid fibrils. When we induced the ultrasonication-dependent fibrillation of β2-microglobulin and insulin monitored by amyloid-specific thioflavin T (ThT) fluorescence, both proteins showed a significant decrease in ThT fluorescence after the burst-phase increase. The decrease in ThT fluorescence was accelerated when the ultrasonic power was stronger, suggesting that this decrease was caused by the partial denaturation of preformed fibrils. The possible intermediates of denaturation retained amyloid-like morphologies, secondary structures, and seeding potentials. Similar denaturation intermediates were also observed when fibrils were denatured by guanidine hydrochloride or sodium dodecyl sulfate. The presence of these denaturation intermediates is consistent with the main-chain-dominated architecture of amyloid fibrils. Moreover, in the three types of denaturation experiments conducted, insulin fibrils were more stable than β2-microglobulin fibrils, suggesting that the relative stability of various fibrils is independent of the method of denaturation.
authors.affiliation: Institute for Protein Research, Osaka University , Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
authors.forename: Sayaka
authors.initials: S
authors.lastname: Noda
authors.affiliation: Institute for Protein Research, Osaka University , Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
authors.forename: Masatomo
authors.initials: M
authors.lastname: So
authors.affiliation: Institute for Protein Research, Osaka University , Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Adachi
authors.affiliation: Department of Biochemistry and MTA-ELTE NAP B Neuroimmunology Research Group, Eötvös Loránd University , Pázmány sétány 1/C, Budapest 1117, Hungary.
authors.forename: József
authors.initials: J
authors.lastname: Kardos
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST) , 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Akazawa-Ogawa
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST) , 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Hagihara
authors.affiliation: Institute for Protein Research, Osaka University , Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Goto
mesh_terms: D000682:Amyloid / Q000737:chemistry*; D000818:Animals; D052160:Benzothiazoles; D002470:Cell Survival / Q000187:drug effects; D019791:Guanidine / Q000494:pharmacology; D006801:Humans; D007328:Insulin / Q000737:chemistry; D016716:PC12 Cells; D066329:Protein Aggregates / Q000187:drug effects; D011489:Protein Denaturation / Q000187:drug effects; D017433:Protein Structure, Secondary; D051381:Rats; D013844:Thiazoles / Q000737:chemistry*; D000069453:Ultrasonic Waves; D001613:beta 2-Microglobulin / Q000737:chemistry / Q000633:toxicity
chemical_list: D000682:Amyloid; D052160:Benzothiazoles; D007328:Insulin; D066329:Protein Aggregates; D013844:Thiazoles; D001613:beta 2-Microglobulin; C009462:thioflavin T; D019791:Guanidine