Salusin-β is an endogenous bioactive peptide that was identified in a human full-length enriched cDNA library using bioinformatics analyses. In our previous study, we found that synthetic salusin-β exhibits antibacterial activity against only Gram-positive microorganisms such as Staphylococcus aureus NBRC 12732. Salusin-β has an ability to depolarize the cytoplasmic membrane of this bacterium, and this phenomenon may be linked to the antibacterial activity of this peptide. A cell-penetrating peptide (CPP), human immunodeficiency virus (HIV)-1 transactivator of transcription (Tat) (49–57) is a short cationic peptide that can traverse cell membranes. In this report, synthetic peptide conjugates of salusin-β and HIV-1 Tat(49–57) showed potent antibacterial activities against both Gram-positive Staphylococcus aureus NBRC 12732 and Gram-negative Escherichia coli NBRC 12734. The synthetic peptides also depolarized the cytoplasmic membrane of Escherichia coli NBRC 12734 as well as Staphylococcus aureus NBRC 12732. These results suggested that HIV-1 Tat(49–57) is a protein transduction domain or CPP that changes the interaction mode between salusin-β and the cell membrane of Escherichia coli NBRC 12734. By binding to HIV-1 Tat(49–57), salusin-β showed a broad antibacterial spectrum regardless of whether the target was a Gram-positive or Gram-negative bacterium.

Salusin-β是一种内源性生物活性肽，可通过生物信息学分析在人全长富集的cDNA文库中鉴定。在我们先前的研究中，我们发现合成的salusin-β仅对革兰氏阳性微生物如金黄色葡萄球菌NBRC 12732表现出抗菌活性。salusin-β具有使该细菌的细胞质膜去极化的能力，这种现象可能与该肽的抗菌活性。细胞穿透肽（CPP），人类免疫缺陷病毒（HIV）-1转录反式激活因子（Tat）（49-57）是一种短阳离子肽，可以穿越细胞膜。在本报告中，salusin-β和HIV-1 Tat（49-57）的合成肽结合物显示出对革兰氏阳性的有效抗菌活性。金黄色葡萄球菌NBRC 12732和革兰氏阴性大肠杆菌NBRC12734。合成肽还使大肠杆菌NBRC 12734和金黄色葡萄球菌NBRC 12732的细胞质膜去极化。这些结果表明HIV-1 Tat（49-57）是一种蛋白质转导域或CPP改变salusin-β与大肠杆菌NBRC 12734细胞膜之间的相互作用方式。通过与HIV-1 Tat（49-57）结合，salusin-β表现出宽泛的抗菌谱，而无论靶标是革兰氏阳性或革兰氏阴性细菌。