Shera Jeanne N, Sun Xiuzhi Susan
Bio-materials & Technology Lab, Department of Grain Science & Industry, Kansas State University, 1980 Kimball Avenue, Manhattan, Kansas 66506, USA.
Biomacromolecules. 2009 Sep 14;10(9):2446-50. doi: 10.1021/bm900388b.
Peptides that undergo a morphological change when exposed to a stimulus have been investigated for their surface and self-assembly properties. Two 15-residue sequences were designed and synthesized for the purpose of determining the role of sequence on surface properties and peptide self-assembly. The KhK (KKKFLIVIGSIIKKK) and Alternating Kh (KFLKKIVKIGKKSII) sequences were synthesized via microwave peptide synthesis according to the automated base-labile Fmoc strategy. Despite having the same amino acid content, KhK solutions exhibited an increase in contact angle with increasing pH, whereas Alternating Kh solutions demonstrated a decrease in contact angle with increasing pH. Further analysis by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed marked differences in the peptide solution and peptide particle morphology. Circular dichroism (CD) spectroscopy indicated that KhK consisted of primarily beta-sheet conformations at acidic and neutral pH. In Alternating Kh CD spectra, random coil conformations were predominant at acidic and neutral pH.
已对暴露于刺激时会发生形态变化的肽的表面和自组装特性进行了研究。为了确定序列对表面特性和肽自组装的作用，设计并合成了两个15个残基的序列。根据自动碱不稳定Fmoc策略，通过微波肽合成法合成了KhK（KKKFLIVIGSIIKKK）和交替Kh（KFLKKIVKIGKKSII）序列。尽管氨基酸含量相同，但KhK溶液的接触角随pH值升高而增加，而交替Kh溶液的接触角随pH值升高而减小。通过透射电子显微镜（TEM）和扫描电子显微镜（SEM）进行的进一步分析表明，肽溶液和肽颗粒形态存在明显差异。圆二色性（CD）光谱表明，KhK在酸性和中性pH值下主要由β-折叠构象组成。在交替Kh的CD光谱中，随机卷曲构象在酸性和中性pH值下占主导地位。
