Libardo M Daben J, Paul Thomas J, Prabhakar Rajeev, Angeles-Boza Alfredo M
Department of Chemistry, University of Connecticut, Storrs, CT, USA.
Department of Chemistry, University of Miami, Coral Gables, FL, USA.
Biochimie. 2015 Jun;113:143-55. doi: 10.1016/j.biochi.2015.04.008. Epub 2015 Apr 17.
The emergence of antibiotic resistant strains of bacteria has resulted in the need to develop more potent antimicrobials that target microorganisms in a novel manner. Antimicrobial Peptides (AMPs) show great potential for drug development because of their broad activity and unique mechanism of action. Several AMPs contain an Amino Terminal Copper and Nickel (ATCUN) binding motif; however, its function has not yet been determined. We have previously demonstrated that the activity of a truncated version of Buforin II (sh-Buforin, RAGLQFPVGRVHRLLRK-NH2) increases by the addition of an ATCUN motif. We now focus our current studies on understanding the effect of: 1) a positively charged ATCUN sequence, and 2) l-to-d amino acid substitution on the hybrid peptides. We identified that the addition of a positively charged ATCUN motif increases the affinity of the ATCUN-AMP for DNA but does not always result in an enhanced antimicrobial activity over a neutral ATCUN motif. The all-d peptides exhibited up to a 32-fold increase in antimicrobial activity compared to the all-l peptides. The larger activity of the all-d peptides is the result of a larger DNA cleavage activity and higher stability towards proteolysis. Cytotoxicity assays determined that, at their MIC, these peptides caused less than 8% hemolysis and, at 128 μM, no toxicity to HeLa and HEK293 cell lines. These results indicate that the ATCUN-AMP hybrids are an attractive alternative for treating infectious diseases and provide key insights into the role of the ATCUN motif in naturally-occurring AMPs.
细菌耐药菌株的出现导致需要开发更有效的抗菌药物，这些药物要以全新的方式作用于微生物。抗菌肽（AMPs）因其广泛的活性和独特的作用机制，在药物开发方面显示出巨大潜力。几种抗菌肽含有氨基末端铜和镍（ATCUN）结合基序；然而，其功能尚未确定。我们之前已经证明，截短版蟾蜍灵II（sh - Buforin，RAGLQFPVGRVHRLLRK - NH2）添加ATCUN基序后活性增强。我们目前的研究重点是了解：1）带正电荷的ATCUN序列，以及2）l - 到d氨基酸取代对杂合肽的影响。我们发现，添加带正电荷的ATCUN基序会增加ATCUN - AMP与DNA的亲和力，但与中性ATCUN基序相比，并不总是能增强抗菌活性。与全l肽相比，全d肽的抗菌活性提高了32倍。全d肽更大的活性是更大的DNA切割活性和对蛋白水解更高稳定性的结果。细胞毒性试验表明，在最低抑菌浓度时，这些肽引起的溶血率低于8%，在128μM时，对HeLa和HEK293细胞系无毒性。这些结果表明，ATCUN - AMP杂合体是治疗传染病的一个有吸引力的选择，并为ATCUN基序在天然抗菌肽中的作用提供了关键见解。
