Pini Alessandro, Giuliani Andrea, Falciani Chiara, Runci Ylenia, Ricci Claudia, Lelli Barbara, Malossi Monica, Neri Paolo, Rossolini Gian Maria, Bracci Luisa
Sezione di Biochimica, Dipartimento di Biologia Molecolare, Università degli Studi di Siena, Via Fiorentina 1, 53100 Siena, Italy.
Antimicrob Agents Chemother. 2005 Jul;49(7):2665-72. doi: 10.1128/AAC.49.7.2665-2672.2005.
A large 10-mer phage peptide library was panned against whole Escherichia coli cells, and an antimicrobial peptide (QEKIRVRLSA) was selected. The peptide was synthesized in monomeric and dendrimeric tetrabranched form (multiple antigen peptide [MAP]), which generally allows a dramatic increase of peptide stability to peptidases and proteases. The antibacterial activity of the dendrimeric peptide against E. coli was much higher than that of the monomeric form. Modification of the original sequence, by residue substitution or sequence shortening, produced three different MAPs, M4 (QAKIRVRLSA), M5 (KIRVRLSA), and M6 (QKKIRVRLSA) with enhanced stability to natural degradation and antimicrobial activity against a large panel of gram-negative bacteria. The MICs of the most potent peptide, M6, were as low as 4 to 8 microg/ml against recent clinical isolates of multidrug-resistant Pseudomonas aeruginosa and members of the Enterobacteriaceae. The same dendrimeric peptides showed high stability to blood proteases, low hemolytic activity, and low cytotoxic effects on eukaryotic cells, making them promising candidates for the development of new antibacterial drugs.
利用一个大型的10聚体噬菌体肽库对完整的大肠杆菌细胞进行淘选，筛选出一种抗菌肽（QEKIRVRLSA）。该肽以单体形式和树枝状四分支形式（多抗原肽[MAP]）合成，这通常能显著提高肽对肽酶和蛋白酶的稳定性。树枝状肽对大肠杆菌的抗菌活性远高于单体形式。通过残基替换或序列缩短对原始序列进行修饰，产生了三种不同的MAP，即M4（QAKIRVRLSA）、M5（KIRVRLSA）和M6（QKKIRVRLSA），它们对自然降解的稳定性增强，对一大类革兰氏阴性菌具有抗菌活性。最有效的肽M6对近期临床分离的多重耐药铜绿假单胞菌和肠杆菌科成员的最低抑菌浓度低至4至8微克/毫升。同样的树枝状肽对血液蛋白酶具有高稳定性、低溶血活性以及对真核细胞的低细胞毒性作用，使其成为开发新型抗菌药物的有潜力的候选物。
