The structure of the individual peptides of the two-peptide bacteriocin plantaricin S, an antimicrobial peptide produced by a Lactobacillus plantarum strain, has been determined in DPC micelles. The two peptides of plantaricin S, Pls-α and Pls-β, form an α-helix from and including residue 8 to 24 with a less structured region around residue 16-19 and an amphiphilic α-helix from and including residue 7 to 23, respectively. Activity assays on single amino acid-substituted GxxxG and GxxxG-like motifs show that substituting the Ser and Gly residues in the G₉xxxG₁₃ motif in Pls-α and the S₁₇xxxG₂₁ motif in Pls-β reduced or drastically reduced the antimicrobial activity. The two-peptide bacteriocin muricidin contains GxxxG-like motifs at similar positions and displays 40-50% amino acid identity with plantaricin S. Activity assays of combinations of the peptides that constitute the bacteriocins plantaricin S and muricidin show that some combinations are highly active. Furthermore, sequence alignments show that the motifs important for plantaricin S activity align with identical motifs in muricidin. Based on sequence comparison and activity assays, a membrane-inserted model of plantaricin S in which the two peptides are oriented antiparallel relative to each other and where the GxxxG and GxxxG-like motifs important for activity come close in space, is proposed.

二肽细菌素 plantaricin S（一种由植物乳杆菌菌株产生的抗菌肽）的各个肽的结构已在 DPC 胶束中确定。 Plantaricin S 的两种肽，Pls-α 和 Pls-β，形成来自残基 8 至 24（包括残基 8 至 24）的 α 螺旋，以及残基 16-19 周围结构较少的区域，以及来自残基 7 至 23（包括残基 7 至 23）的两亲性 α 螺旋， 分别。对单氨基酸取代的 GxxxG 和 GxxxG 样基序的活性测定表明，取代 Pls-α 中的 G ₉ xxxG ₁₃基序和 Pls-β 中的 S _1​​7 xxxG ₂₁基序中的 Ser 和 Gly 残基可降低或显着降低抗菌活性。活动。二肽细菌素muricidin在相似位置含有GxxxG样基序，并且与plantaricin S显示出40-50%的氨基酸同一性。对构成细菌素plantaricin S和muricidin的肽的组合的活性测定表明，一些组合具有高活性。此外，序列比对显示，对 plantaricin S 活性重要的基序与 muricidin 中的相同基序对齐。基于序列比较和活性测定，提出了 plantaricin S 的膜插入模型，其中两种肽相对于彼此反向平行取向，并且对于活性重要的 GxxxG 和 GxxxG 样基序在空间上接近。