Multipurpose isothiocyanyl alanine/lysine: Use as solvatochromic IR probes and in site specific labeling/ligation of short peptides
摘要:
The solvatochromic IR responsivity of small side chain-NCS in two unexplored unnatural amino acids, isothiocyanyl alanine ((NCS)Ala = Ita) and lysine ((NCS)Lys = Itl), without perturbing the conformation is demonstrated in two designed short tripeptide (BocAla-(NCS)Ala-Ala-OMe) and hexapeptide (BocLeu-ValPhe- Phe-(NCS)Lys-Gly-OMe). Demonstration of site specific fluorescent labeling in both the peptides and ligation type reaction in (NCS)Lys indicates the novelty of these two amino acids as alternative to the available canonical amino acids. (C) 2018 Published by Elsevier Ltd.
The synthesis and characterization of a series of ferrocene (Fc) peptide conjugates containing the amino acid valine is reported, where the peptide substituents are part of the hydrophobic sequence of the amyloid β-peptide. The hydrogen-bonding (H-bonding) interaction in these compounds is studied by variable temperature 1H NMR spectroscopy. The solid-state structures, determined by single crystal X-ray
报道了一系列包含氨基酸缬氨酸的二茂铁(Fc)肽缀合物的合成和表征,其中肽取代基是淀粉样β-肽的疏水序列的一部分。通过可变温度1 H NMR光谱研究了这些化合物中的氢键(H键)相互作用。通过单晶X射线晶体学确定的两种结合物(Fc [CO-Leu-Val-OMe] 2 1和Fc [CO-Gly-Val-OH] 2 6的固态结构)的报告。两种结构均通过分子内的H键稳定,表现出熟悉的“ Herrick基序”,涉及邻近氨基酸的近端酰胺NH和酰胺CO。该基序足够刚性,并且如CD研究所建议的那样保持在溶液中。但是,在缀合物1和6上观察到的分子间H键合模式显着不同,导致超分子体系结构非常不同。对于缀合物1,观察到一组更常规的头尾堆叠相互作用,其通过单个分子之间的β-折叠样H-键相互作用而稳定。但是,对于共轭6因此,C端酸基团的存在以及Gly接头的柔韧性使得能够形成更开放的结构,该结构包含被溶剂分子占据的疏水性通道。