Zhang Xingang, van der Donk Wilfred A
Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
Methods Enzymol. 2009;462:117-34. doi: 10.1016/S0076-6879(09)62006-1.
The lantibiotics are a class of ribosomally synthesized and posttranslationally modified peptide antibiotics containing the thioether cross-links lanthionine (Lan) and 3-methyllanthionine (MeLan) and typically also the dehydroamino acids dehydroalanine (Dha) and (Z)-dehydrobutyrine (Dhb). The modifications are formed by dehydration of Ser/Thr residues to produce the Dha and Dhb structures, and subsequent conjugate additions of Cys residues onto the unsaturated amino acids to form thioether rings (Lan and MeLan). Because of their ribosomal origin, investigations of the substrate specificity of lantibiotic synthetases have typically focused on site-directed mutagenesis. With the in vitro reconstitution of lacticin 481 synthetase, its substrate specificity was explored in much greater detail by the incorporation of a series of nonproteinogenic Ser, Thr, and Cys analogues into a truncated prelacticin peptide LctA using a combination of solid-phase peptide synthesis (SPPS) and expressed protein ligation (EPL). The strategy described can be used for the growing number of ribosomally synthesized and posttranslationally modified natural products such as the microcins and patellamides.
羊毛硫抗生素是一类核糖体合成且经翻译后修饰的肽抗生素，含有硫醚交联键的丙氨酸（Lan）和3-甲基丙氨酸（MeLan），通常还含有脱氢氨基酸脱氢丙氨酸（Dha）和（Z）-脱氢丁氨酸（Dhb）。这些修饰是由丝氨酸/苏氨酸残基脱水形成Dha和Dhb结构，随后半胱氨酸残基共轭加成到不饱和氨基酸上形成硫醚环（Lan和MeLan）。由于其核糖体起源，对羊毛硫抗生素合成酶底物特异性的研究通常集中在定点诱变上。通过乳酸链球菌素481合成酶的体外重构，利用固相肽合成（SPPS）和表达蛋白连接（EPL）相结合的方法，将一系列非蛋白质原性的丝氨酸、苏氨酸和半胱氨酸类似物掺入截短的前乳酸链球菌素肽LctA中，对其底物特异性进行了更详细的探索。所描述的策略可用于越来越多的核糖体合成且经翻译后修饰的天然产物，如微小菌素和海鞘酰胺。
