Identifying reducing and capping sites of protein-encapsulated gold nanoclusters

Yu Chen Hsu, Mei Jou Hung, Yi An Chen, Tsu Fan Wang, Ying Ru Ou, Shu Hui Chen

研究成果: Article同行評審

14 引文 斯高帕斯(Scopus)

摘要

The reducing and capping sites along with their local structure impact photo properties of the red bovine serum albumin-capped Au nanocluster (BSA-AuNC), however, they are hard to identify. We developped a workflow and relevant techniques using mass spectrometry (MS) to identify the reducing and capping sites of BSA-AuNCs involved in their formation and fluorescence. Digestion without disulfide cleavages yielded an Au core fraction exhibiting red fluorescence and [AunSm] ion signals and a non-core fraction exhibiting neither of them. The core fraction was identified to mainly be comprised of peptides containing cysteine residues. The fluorescence and [AunSm] signals were quenched by tris(2-carboxyethyl)phosphine, confirming that disulfide groups were required for nanocluster stabilization and fluorescence. By MS sequencing, the disulfide pairs, C75–C91/C90–C101 in domain IA, C315–C360/C359–C368 in domain IIB, and C513–C558/C557–C566 in domain IIIB, were identified to be main capping sites of red AuNCs. Peptides containing oxidized cysteines (sulfinic or cysteic acid) were identified as reducing sites mainly in the non-core fraction, suggesting that disulfide cleavages by oxidization and conformational changes contributed to the subsequent growth of nanoclusters at nearby intact disulfide pairs. This is the first report on precise identification of the reducing and capping sites of BSA-AuNCs.

原文English
文章編號1630
期刊Molecules
24
發行號8
DOIs
出版狀態Published - 2019 4月 25

All Science Journal Classification (ASJC) codes

  • 分析化學
  • 化學(雜項)
  • 分子醫學
  • 藥學科學
  • 藥物發現
  • 物理與理論化學
  • 有機化學

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