Chem. J. Chinese Universities ›› 2024, Vol. 45 ›› Issue (11): 20240192.doi: 10.7503/cjcu20240192

• Article • Previous Articles     Next Articles

Analysis of N-Terminal Fragment of β⁃ Amyloid Peptides Using an Aerolysin Nanopore

CHEN Tianze1, HU Fangzhou2, LIN Xubo3, YING Yilun4, ZOU Aihua1()   

  1. 1.College of Chemistry and Materials Science,Shanghai Normal University,Shanghai 200237,China
    2.School of Chemical and Molecular Engineering,East China University of Science and Technology,Shanghai 200237,China
    3.School of Medical Science and Engineering,Beihang University,Beijing 100191,China
    4.State Key Laboratory of Life Analytical Chemistry,School of Chemistry and Chemical Engineering,Nanjing University,Nanjing 210023,China
  • Received:2024-04-17 Online:2024-11-10 Published:2024-05-28
  • Contact: ZOU Aihua E-mail:aihuazou@shnu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(22334006)

Abstract:

Alzheimer’s disease(AD) is one of the most common diseases caused by multiple neurodegenerative protein misfolding and aggregation disorders. Abnormal deposition of amyloid protein caused by β-amyloid(Aβ) peptides has been suggested as a possible predisposing factor for Alzheimer’s disease. Unlike human Aβ peptide, rodent Aβ peptide rarely has these characteristic lesions. The difference between rodent Aβ peptide and human Aβ peptide is that the 5th, 10th and 13th amino acids(Arg, Tyr, His) are replaced by Gly, Phe and Arg, respectively. In this study, molecular dynamics simulation and nanopore-based single molecule detection technology were used to study the structural differences between human Aβ1—15 and rodent Aβ1—15. The experimental results show that rodent Aβ1—15 has lower blocking frequency and energy barrier when passing through nanopore than human Aβ1—15, which proves that aerolysin nanopore can distinguish Aβ1—15 with small structural differences. Furthermore, the interaction between Aβ1—15 and sulfate ion was studied by using sulfate K2SO4 as a simplified model of glycosaminoglycan (glycosaminoglycans, GAGs). Statistical analysis showed that both peptides could bind to sulfate ions and reduce their capture frequency by aerolysin nanopore, reducing the capture frequency of human Aβ1—15 by 25% and rodent Aβ1—15 by 59%. However, after the addition of sulfate ion, there was a significant difference in the dwell time of the two peptides. Compared with the results in the absence of sulfate, the dwell time of human Aβ1—15 increased by 14% and that of rodent Aβ1—15 decreased by 7%. It is inferred from the experimental results that the different sequences and conformations of the two peptides lead to different binding ways and binding intensity to sulfate ions, which have different effects on the translocation behavior. This study is helpful to better screen small molecular inhibitors and further promote the diagnosis and treatment of Alzheimer’s disease.

Key words: β-Amyloid, Aerolysin, Single molecule analysis of peptide, Biological nanopores

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