Bioconjugation with Thiols by Benzylic Substitution
作者:Kenji Watanabe、Takashi Ohshima
DOI:10.1002/chem.201706149
日期:2018.3.15
A benzylic substitution of 3‐indolyl(hydroxyl)acetate derivatives with thiols proceeded specifically in the presence of amino, carboxy, and phosphate groups in weakly acidic aqueoussolutions under nearly physiological condition, while no reaction occurred at pH over 7. Kinetic studies revealed that the reaction followed second‐order kinetics (first‐order in the reactant and first‐order in thiol) in
在弱酸性水溶液中,在接近生理条件下,氨基,羧基和磷酸酯基团的存在下,3-氨基吲哚基(羟基)乙酸酯衍生物被苄基取代的过程特别是在氨基,羧基和磷酸基团存在的情况下进行,而在pH超过7的条件下没有反应发生。动力学研究表明与醇的常见苄基取代的S N 1机理相反,该反应遵循二级动力学(反应物中的一级动力学和硫醇中的一级动力学)。使用几种模型蛋白,例如溶菌酶,胰岛素,胰蛋白酶和血清白蛋白,证明了本方法对生物大分子进行功能化的效用。修饰后,溶菌酶在溶菌微球菌细胞裂解中的催化生物活性被完全保留。
Indolylalkyltriphenylphosphonium Analogues Are Membrane-Depolarizing Mycobactericidal Agents
作者:Ming Li、Samuel A. Nyantakyi、Pooja Gopal、Dinah binte Aziz、Thomas Dick、Mei-Lin Go
DOI:10.1021/acsmedchemlett.7b00287
日期:2017.11.9
Agents that selectively target the mycobacterial membrane could potentially shorten treatment time for tuberculosis, reduce relapse, and curtail emergence of resistant strains. The lipophilicity and extensive charge-delocalized state of the triphenylphosphonium cation strongly favor accumulation within bacterial membranes. Here, we explored the antimycobacterial activities and membrane-targeting properties of indolylalkyltriphenylphosphonium analogues. The most active analogues preferentially inhibited growth of Mycobacterium tuberculosis H37Rv (MIC50 2-4 mu M) and were bactericidal against Mycobacterium bovis BCG (MBC99 3 mu M). In spite of their propensity to accumulate within membranes, we found no evidence that these compounds permeabilized mycobacterial membranes or induced cell-envelope stress. Our investigations indicated that their bacterical effects stem from sustained depolarization of mycobacterial membranes and ensuing disruptive effects on electron transfer and cell division.