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Role of monomer arrangement in the amyloid self-assembly.
Portillo, Alexander; Hashemi, Mohtadin; Zhang, Yuliang; Breydo, Leonid; Uversky, Vladimir N; Lyubchenko, Yuri L.
Afiliação
  • Portillo A; Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198-6025, USA.
  • Hashemi M; Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198-6025, USA.
  • Zhang Y; Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198-6025, USA.
  • Breydo L; Department of Molecular Medicine, USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd. MDC07, Tampa, FL 33647, USA.
  • Uversky VN; Department of Molecular Medicine, USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd. MDC07, Tampa, FL 33647, USA; Department of Biological Science, Faculty of Science, King Abdulaziz University, PO Box 80203, Jeddah 21
  • Lyubchenko YL; Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198-6025, USA. Electronic address: ylyubchenko@unmc.edu.
Biochim Biophys Acta ; 1854(3): 218-28, 2015 Mar.
Article em En | MEDLINE | ID: mdl-25542374
ABSTRACT
Assembly of amyloid proteins into aggregates requires the ordering of the monomers in oligomers and especially in such highly organized structures as fibrils. This ordering is accompanied by structural transitions leading to the formation of ordered ß-structural motifs in proteins and peptides lacking secondary structures. To characterize the effect of the monomer arrangements on the aggregation process at various stages, we performed comparative studies of the yeast prion protein Sup35 heptapeptide (GNNQQNY) along with its dimeric form CGNNQQNY-(d-Pro)-G-GNNQQNY. The (d-Pro)-G linker in this construct is capable of adopting a ß-turn, facilitating the assembly of the dimer into the dimeric antiparallel hairpin structure (AP-hairpin). We applied Atomic Force Microscopy (AFM) techniques to follow peptide-peptide interactions at the single molecule level, to visualize the morphology of aggregates formed by both constructs, thioflavin T (ThT) fluorescence to follow the aggregation kinetics, and circular dichroism (CD) spectroscopy to characterize the secondary structure of the constructs. The ThT fluorescence data showed that the AP-hairpin aggregation kinetics is insensitive to the external environment such as ionic strength and pH contrary to the monomers the kinetics of which depends dramatically on the ionic strength and pH. The AFM topographic imaging revealed that AP-hairpins primarily assemble into globular aggregates, whereas linear fibrils are primary assemblies of the monomers suggesting that both constructs follow different aggregation pathways during the self-assembly. These morphological differences are in line with the AFM force spectroscopy experiments and CD spectroscopy measurements, suggesting that the AP-hairpin is structurally rigid regardless of changes of environmental factors.
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Texto completo: 1 Base de dados: MEDLINE Assunto principal: Fatores de Terminação de Peptídeos / Proteínas de Saccharomyces cerevisiae Idioma: En Ano de publicação: 2015 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Fatores de Terminação de Peptídeos / Proteínas de Saccharomyces cerevisiae Idioma: En Ano de publicação: 2015 Tipo de documento: Article