Pseudomycoicidin, a Class II Lantibiotic from Bacillus pseudomycoides
Pseudomycoicidin, a Class II Lantibiotic from Bacillus pseudomycoides
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DOI：
10.1128/aem.00299-15
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发表时间：
2015-05-01
影响因子：
4.4
通讯作者：
Bierbaum, Gabriele
中科院分区：
文献类型：
--
作者：
Basi-Chipalu, Shradha;Dischinger, Jasmin;Bierbaum, Gabriele
抗生素是由核糖体合成的具有大量翻译后修饰的抗菌肽。它们的特征是独特的氨基酸羊毛硫氨酸和甲基羊毛硫氨酸，它们是通过Ser/Thr残基的脱水和所得到的脱水氨基酸与Cys残基的连接而引入的。利用NCBI数据库中的麦芽糖素生物合成酶(MRS-M)进行BLAST搜索，发现在拟青霉芽孢杆菌DSM-12442中存在一个新的II类抗生素基因簇。在该菌株的细胞洗涤提取物中检测到一种具有抗革兰氏阳性细菌活性的抗菌物质的产生。该物质被部分纯化，质谱分析预测活性部分含有2,786Da的多肽。为了进一步鉴定可能的抗生素，预测的生物合成基因在大肠杆菌中进行了异源表达。前肽(PSEA)和相应的修饰酶(PseM)的共表达导致了具有相应质量的修饰肽的产生，8种可能的脱水中有4种进行了脱水，并支持4种硫醚和1种二硫键的存在。经过蛋白质水解法去除前导体后，核心肽显示出抗菌活性。综上所述，假霉菌素是一种在大肠杆菌中异源产生的具有抗菌活性的新型抗生素。
Lantibiotics are ribosomally synthesized antimicrobial peptides with substantial posttranslational modifications. They are characterized by the unique amino acids lanthionine and methyllanthionine, which are introduced by dehydration of Ser/Thr residues and linkage of the resulting dehydrated amino acids with Cys residues. BLAST searches using the mersacidin biosynthetic enzyme (MrsM) in the NCBI database revealed a new class II lantibiotic gene cluster in Bacillus pseudomycoides DSM 12442. Production of an antimicrobial substance with activity against Gram-positive bacteria was detectable in a cell wash extract of this strain. The substance was partially purified, and mass spectrometric analysis predicted a peptide of 2,786 Da in the active fraction. In order to characterize the putative lantibiotic further, heterologous expression of the predicted biosynthetic genes was performed in Escherichia coli. Coexpression of the prepeptide (PseA) along with the corresponding modification enzyme (PseM) resulted in the production of a modified peptide with the corresponding mass, carrying four out of eight possible dehydrations and supporting the presence of four thioether and one disulfide bridge. After the proteolytic removal of the leader, the core peptide exhibited antimicrobial activity. In conclusion, pseudomycoicidin is a novel lantibiotic with antimicrobial activity that was heterologously produced in E. coli.