蜂毒肽类似物的合成和生物活性研究

Studies on Synthesis and Biological Activities of Analogues of Melittin

Melittin(GIGAVLKVLTTGLPALISWIKRKRQQ— NH2 )是蜂毒中含 2 6个氨基酸残基的多肽 ,具有抗菌和溶血等生物活性 ,是典型的阳离子抗菌肽 .本文设计合成了蜂毒肽 C端 1 5残基肽片段(GLPALISWIKRKRQQ— NH2 )及其类似物 (1 5残基 ) .研究了 Melittin及这些合成肽的抗菌活性、溶血活性、疏水性及二级结构 .结果表明 ,合成的类似物的溶血活性明显降低 ,抗菌活性基本保留 ,且与其疏水性相关 .类似物中与碱性氨基酸簇 (KRKR)距离较远的残基的疏水性对其抗菌活性有较大的贡献 .多肽溶血与抗菌机理不同 .类似物的抗菌活性和溶血活性与其二级结构 (α-螺旋结构 )

Melittin(GIGAVLKVLTTGLPALISWIKRKRQQ-NH_2), a 26-residue peptide, is the major component of the venom of the honey bee Apis mellifera, exhibits highly potent antibacterial activity in addition to its hemolytic activity. A peptide corresponding to Melittin′s C-terminal 15 residues and 4 analogues with 15 residues, respectively, were designed and synthesized. The pure peptides were obtained by semi-preparative RP-HPLC. Analytical RP-HPLC showed a single peak and amino acid analysis showed that the peptides had expected amino acid compositions. Antibiotic activities, hemolytic activities, hydrophobicities and secondary structures of the peptides were studied. All these analogues exhibited potent antibacterial activities and had much decreased abilities to lyse human red blood cells. The antibiotic activities were roughly correlated with the hydrophobicities. The hydrophobicities of the residues farther from the basic cluster(KRKR), however, contributed more to the antibiotic activities. While the mechanism of hemolysis of peptides is not the same as antibacterial action. No clear correlation between the hydrophobicities or the hemolytic activities and the secondary structures(α-helical structures) was found.