Blöcher D, Freisleben H J, Becker G, Jung G, Ring K
Gustav-Embden-Zentrum der Biologischen Chemie, Johann Wolfgang Goethe-Universität, Frankfurt/Main, F.R.G.
Biochim Biophys Acta. 1991 Jun 18;1065(2):160-6. doi: 10.1016/0005-2736(91)90226-x.
Four analogues of the membrane-modifying, alpha-helical polypeptide antibiotic alamethicin were synthesized. the alpha-helical deca-, undeca-, heptadeca-, and icosapeptides were mixed with the main tetraether lipid of the Archaebacterium Thermoplasma acidophilum (MPL), dipalmitoylphosphatidylcholine (DPPC) and dihexadecylmaltosylglycerol (DHMG) in various ratios and the modification of the lipid phase transition was determined by differential thermal analysis (DTA). The polypeptides form mixed phases with MPL and DPPC, however, not with DHMG. Heptadeca- and icosapeptide exert a much stronger reduction of enthalpy (delta H) than deca- and undecapeptide and bind about 0.5 molecule of MPL (or one molecule of DPPC) per peptide molecule. delta H of the DPPC pretransition is reduced by the deca- and the undecapeptides and completely disappears with heptadeca- and icosapeptides (at 0.2 mole of peptide/mole of lipid). The modulation of the melting point Tm by the incorporation of peptides is more pronounced with MPL than with DPPC, the heptadecapeptide exhibiting the strongest reduction (with MPL) and the strongest broadening of the transition peak (with DPPC). Helix length, amphiphilicity and charge of the polypeptides can be correlated with the observed modifications of the lipid phase transitions.
合成了四种具有膜修饰作用的α-螺旋多肽抗生素阿拉米辛类似物。将α-螺旋十肽、十一肽、十七肽和二十肽与嗜热栖热菌的主要四醚脂质（MPL）、二棕榈酰磷脂酰胆碱（DPPC）和二己基麦芽糖基甘油（DHMG）以不同比例混合，并通过差示热分析（DTA）测定脂质相变的变化。这些多肽与MPL和DPPC形成混合相，但不与DHMG形成混合相。十七肽和二十肽比十肽和十一肽对焓（ΔH）的降低作用更强，且每个肽分子结合约0.5个MPL分子（或1个DPPC分子）。十肽和十一肽可降低DPPC预转变的ΔH，而十七肽和二十肽（在0.2摩尔肽/摩尔脂质时）可使其完全消失。与DPPC相比，MPL中肽的掺入对熔点Tm的调节更为明显，十七肽对熔点的降低作用最强（对MPL而言），对转变峰的展宽作用最强（对DPPC而言）。多肽的螺旋长度、两亲性和电荷与观察到的脂质相变变化相关。
