Thermodynamic Scale of β-Amino Acid Residue Propensities for an α-Helix-like Conformation
作者:Brian F. Fisher、Seong Ho Hong、Samuel H. Gellman
DOI:10.1021/jacs.8b05162
日期:2018.8.1
These measurements depend on formation of a parallel coiled-coil tertiary structure when two peptide segments become linked by thioester formation. One peptide segment contains a "guest" site that accommodates diverse β residues and is distal to the coiled-coil interface. We find that helix propensity is influenced by sidechain placement within the β residue [β3 (sidechain adjacent to nitrogen) slightly
Exploration of Diverse Reactive Diad Geometries for Bifunctional Catalysis via Foldamer Backbone Variation
作者:Zebediah C. Girvin、Samuel H. Gellman
DOI:10.1021/jacs.8b05869
日期:2018.10.3
What is the best spatial arrangement of a pair of reactive groups for bifunctional catalysis of a chemical transformation? The conformational versatility of proteins allows reactive group geometry to be explored and optimized via evolutionary selection, but it has been difficult for chemists to identify synthetic scaffolds that allow broad comparative evaluation among alternative reactive group geometries
Disclosed are polypeptide compounds containing at least one residue comprising a cyclically-constrained &ggr;-amino acid residue. The compounds have the formula
1
where A is a hydrogen, hydroxy, amino- or carboxy-protecting group, Y is a single bond or a prolyl-containing linking group, and X and Y are &ggr;-amino acid residues, provided that one of X or Y is a conformationally-restrained &ggr;-amino acid residue, and “a,” “c,” and “d” are positive integers. The compounds find use as non-enzymatically degradable probes to mimic protein behavior in solution.
Linker substitution influences succinimide ring hydrolysis equilibrium impacting the stability of attachment to antibody–drug conjugates
作者:Lu Wang、Adrian D. Hobson、Paulin L. Salomon、Julia Fitzgibbons、Jianwen Xu、Sean McCarthy、Kan Wu、Ying Jia、Axel Hernandez、Xiang Li、Zhou Xu、Zhongyuan Wang、Yajie Yu、Junxian Li、Lin Tao
DOI:10.1039/d3md00569k
日期:——
Maleimide chemistry is widely used in antibody–drugconjugate (ADC) generation to connect drugs to antibodies through a succinimide linker. The resulting ADC is prone to payload loss via a reverse Michael reaction, leading to premature drug release in vivo. Complete succinimide hydrolysis is an effective strategy to overcome the instability of ADC. However, we discovered through previous work that
马来酰亚胺化学广泛用于抗体-药物偶联物 (ADC) 生成,通过琥珀酰亚胺接头将药物与抗体连接起来。所得 ADC 容易通过反向 Michael 反应发生有效载荷损失,导致药物在体内过早释放。完全琥珀酰亚胺水解是克服 ADC 不稳定性的有效策略。然而,我们通过以前的工作发现,水解的琥珀酰亚胺环在储存过程中和热应力条件下可以在液体制剂中再次闭合。在这项工作中,设计了一组具有水解易发生基团的马来酰亚胺接头。制备相应的 ADC 并经受热应力条件。测量琥珀酰亚胺水解和药物释放的程度,并计算接头的 SEC 、 DAR 、 pI 和 clog P 等 ADC 性质。我们的结果表明,尽管所有这些基团都提高了水解速率,但它们对维持开放构象中的水解琥珀酰亚胺环和液体制剂中 ADC 稳定性的影响不同。
3-Aminopyrrolidine-4-carboxylic acid as versatile handle for internal labeling of pyrrolidinyl PNA
Conformationally restricted pyrrolidinyl PNAs with an alpha/beta-dipeptide backbone consisting of a nucleobase-modified proline and a cyclic five-membered amino acid spacer such as (1S,2S)-2-aminocyclopentanecarboxylic acid (ACPC) (acpcPNA) can form very stable hybrids with DNA with high Watson-Crick base pairing specificity. This work aims to explore the effect of incorporating 3-aminopyrrolidine-4-carboxylic acid (APC), which is isosteric to the ACPC spacer, into the acpcPNA. It is expected that the modification should not negatively affect the DNA binding properties, and that the additional nitrogen atom in the APC should provide a handle for internal modification. Orthogonally-protected (N-3-Fmoc/N-1-Boc and N-3-Fmoc/N-1-Tfa) APC monomers have been successfully synthesized and incorporated into the acpcPNA by Fmoc-solid-phase peptide synthesis. T-m, UV and CD spectroscopy confirmed that the (3R,4S)-APC could substitute the (1S,2S)-ACPC spacer in the acpcPNA with only slightly decreasing the stability of the hybrids formed between the modified acpc/apcPNA and DNA. In contrast, the (3S,4R) enantiomer of APC caused substantial destabilization of the hybrids. Furthermore, a successful on-solid-support internal labeling of the acpc/apcPNA via amide bond formation between pyrene-1-carboxylic acid or 4-(pyrene-1-yl) butyric acid and the pyrrolidine nitrogen atom of the APC spacer has been demonstrated. Fluorescence properties of the pyrene-labeled acpc/apcPNAs are sensitive to their hybridization states and can readily distinguish between complementary and single-mismatched DNA targets. (C) 2011 Elsevier Ltd. All rights reserved.