Scholarlink

<p>The self-assembly of the cobaltabis(dicarbollide) (COSAN) anionic boron clusters into micelles above a critical micelle concentration (cmc) of 10–20&#xa0;mM and its behavior as “sticky nano-ions” facilitating controlled protein aggregation have been previously investigated using scattering techniques. These techniques effectively provide average structural parameters but, when applied to colloidal systems, often rely on models assuming polydispersity or anisotropic shapes. Here, we employed sedimentation velocity analytical ultracentrifugation (SV-AUC), which offers the ability to resolve discrete species. We revisited two key questions: (1) the aggregation behavior of COSAN into micelles, a topic still under debate, and (2) the nature of the protein assemblies induced by COSAN, specifically their size/shape distribution and aggregation number. SV-AUC confirms the cmc of COSAN of 16&#xa0;mM and reveals that COSAN micelles exhibit low aggregation numbers (8 in water and 14 in dilute salt), consistent with recent hypotheses. It shows that COSAN promotes myoglobin aggregation into discrete oligomeric species with well-defined aggregation numbers, such as dimers, tetramers, and higher-order assemblies, depending on the COSAN-to-protein ratio. COSAN binding could be quantified at the lower COSAN/myoglobin ratios. For example, at ratio 5, myoglobin monomer (25%) binds about two COSANs, dimer (45%) about 14 COSANs, and there are ≈ 30% very large aggregates. These results provide clarity on the discrete nature of COSAN micelle aggregation and protein assembly. This study highlights the complementary role of SV-AUC in understanding supramolecular assemblies, offering useful insights into the behavior of COSAN nano-ions and their interactions with biomacromolecules.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Analytical ultracentrifugation as a tool for exploring COSAN assemblies

  • 期刊论文

  • 发表日期：

    2025年4月23日

查看全文
  • Hussein Fakhouri,
  • Caroline Mas,
  • Aline Le Roy,
  • Estelle Marchal,
  • Coralie Pasquier,
  • Olivier Diat,
  • Pierre Bauduin,
  • Christine Ebel

摘要

The self-assembly of the cobaltabis(dicarbollide) (COSAN) anionic boron clusters into micelles above a critical micelle concentration (cmc) of 10–20 mM and its behavior as “sticky nano-ions” facilitating controlled protein aggregation have been previously investigated using scattering techniques. These techniques effectively provide average structural parameters but, when applied to colloidal systems, often rely on models assuming polydispersity or anisotropic shapes. Here, we employed sedimentation velocity analytical ultracentrifugation (SV-AUC), which offers the ability to resolve discrete species. We revisited two key questions: (1) the aggregation behavior of COSAN into micelles, a topic still under debate, and (2) the nature of the protein assemblies induced by COSAN, specifically their size/shape distribution and aggregation number. SV-AUC confirms the cmc of COSAN of 16 mM and reveals that COSAN micelles exhibit low aggregation numbers (8 in water and 14 in dilute salt), consistent with recent hypotheses. It shows that COSAN promotes myoglobin aggregation into discrete oligomeric species with well-defined aggregation numbers, such as dimers, tetramers, and higher-order assemblies, depending on the COSAN-to-protein ratio. COSAN binding could be quantified at the lower COSAN/myoglobin ratios. For example, at ratio 5, myoglobin monomer (25%) binds about two COSANs, dimer (45%) about 14 COSANs, and there are ≈ 30% very large aggregates. These results provide clarity on the discrete nature of COSAN micelle aggregation and protein assembly. This study highlights the complementary role of SV-AUC in understanding supramolecular assemblies, offering useful insights into the behavior of COSAN nano-ions and their interactions with biomacromolecules.