Dipartimento di Scienze per gli Alimenti, la Nutrizione e l'Ambiente, DeFENS, Università degli Studi di Milano, Via Celoria 2, 20133, Milano, Italy.
Dipartimento di Scienze Chimiche, Università degli Studi di Catania, Viale Andrea Doria 6, 95125, Catania, Italy.
Langmuir. 2020 Nov 17;36(45):13535-13544. doi: 10.1021/acs.langmuir.0c02266. Epub 2020 Nov 2.
The influence of free fatty acids (FFAs) on the nisin-membrane interaction was investigated through micro-DSC and fluorescence spectroscopy. A simple but informative model membrane was prepared (5.7 DMPC:3.8 DPPS:0.5 DOPC molar ratio) by considering the presence of different phospholipid headgroups in charge and size and different phospholipid tails in length and unsaturation level, allowing the discrimination of the combined interaction of nisin and FFAs with the single phospholipid constituents. The effects of six FFAs on membrane stability were evaluated, namely two saturated FFAs (palmitic acid and stearic acid), two monounsaturated FFAs (-unsaturated oleic acid and -unsaturated elaidic acid) and two -polyunsaturated FFAs (ω-6 linoleic acid and ω-3 docosahexaenoic acid). The results permitted assessment of a thermodynamic picture of such interactions which indicates that the peptide-membrane interaction does not overlook the presence of FFAs within the lipid bilayer since both FFAs and nisin are able to selectively promote thermodynamic phase separations as well as a general lipid reorganization within the host membrane. Furthermore, the magnitude of the effects may be different depending on the FFA chemical structure as well as the membrane lipid composition.
通过微量差示扫描量热法和荧光光谱法研究了游离脂肪酸（FFAs）对乳链菌肽-膜相互作用的影响。通过考虑带电荷和大小不同的磷脂头部基团以及长度和不饱和度不同的不同磷脂尾部，制备了一个简单但信息量丰富的模型膜（5.7 DMPC：3.8 DPPS：0.5 DOPC 摩尔比），允许区分乳链菌肽和 FFAs 与单一磷脂成分的组合相互作用。评估了六种 FFAs 对膜稳定性的影响，即两种饱和 FFAs（棕榈酸和硬脂酸）、两种单不饱和 FFAs（-不饱和油酸和 -不饱和反油酸）和两种 -多不饱和 FFAs（ω-6 亚油酸和 ω-3 二十二碳六烯酸）。结果允许评估这种相互作用的热力学图，表明肽-膜相互作用不会忽略脂质双层内 FFAs 的存在，因为 FFAs 和乳链菌肽都能够选择性地促进热力学相分离以及宿主膜内的一般脂质重排。此外，影响的大小可能因 FFA 化学结构以及膜脂组成而异。
