Effects of Anions on Nanostructuring of Cationic Amphiphilic Peptides

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• 作者：Meiwen Cao ; Yuming Wang ; Xin Ge ; Changhai Cao ; Jing Wang ; Hai Xu ; Daohong Xia ; Xiubo Zhao ; Jian R. Lu
• 刊名：Journal of Physical Chemistry B
• 出版年：2011
• 出版时间：October 20, 2011
• 年：2011
• 卷：115
• 期：41
• 页码：11862-11871
• 全文大小：1153K
• 年卷期：v.115,no.41(October 20, 2011)
• ISSN：1520-5207

文摘

The effects of addition of a series of stoichiometric salts on the nanostructuring of cationic amphiphilic peptides have been investigated through the combination of atomic force microscopy (AFM), circular dichroism (CD), and turbidity measurements. The results revealed that anions had more pronounced effects than cations in tuning the nanostructures formed from these peptides. Addition of ClO₃^{鈥?/sup>, NO₃鈥?/sup>, and Br鈥?/sup> could stabilize the primary nanostructures (nanostacks, nanospheres, or short nanorods) formed by A₉K and I₃K and effectively inhibit their growth into longer nanostructures (nanorods or nanotubes). In contrast, the anions of Cl鈥?/sup>, SO₄2鈥?/sup>, HPO₄2鈥?/sup>, PO₄3鈥?/sup>, and C₆H₅O₇3鈥?/sup> (citrate) favored the axial growth of these peptides to form long intersecting nanofibrils and led to an increase in diameter and surface roughness, as well, clearly enhancing their propensity for nanostructuring. The efficiency of different anions in promoting the growth of peptide nanoaggregates into larger ones could be ordered as ClO₃鈥?/sup> < NO₃鈥?/sup> 鈮?Br鈥?/sup> < Cl鈥?/sup> < SO₄2鈥?/sup> < HPO₄2鈥?/sup> < PO₄3鈥?/sup> < C₆H₅O₇3鈥?/sup>, broadly consistent with the Hofmeister anion sequence. These observations were well rationalized by considering different aspects of direct interactions of the anions with the peptide molecules.}