Wang Ye, Morton James D, Bekhit Alaa El-Din A, Carne Alan, Mason Susan L
Department of Wine, Food and Molecular Biosciences, Lincoln University, P.O. Box 84, Lincoln 7674, New Zealand.
Department of Food Science, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand.
Foods. 2021 Jun 7;10(6):1305. doi: 10.3390/foods10061305.
Although the bioactivities of bovine lactoferrin have been extensively investigated, little is known about deer milk lactoferrin bioactivity and its amino acid sequence. This research investigated the amino acid sequence of deer lactoferrin and the antimicrobial activities of two lactoferrin-encrypted peptides; lactoferricin (Lfcin) and lactoferrampin (Lfampin). Deer lactoferrin was found to have a molecular weight of 77.1 kDa and an isoelectric point of 7.99, which are similar to that of bovine lactoferrin, 78 kDa and pI 7.9. Deer lactoferrin contains 707 amino acids, one amino acid less than bovine lactoferrin, and has 92% homology with bovine lactoferrin. Deer lactoferricin exhibited strong antimicrobial activity against American Type Culture Collection (ATCC) 25922 and ATCC 4356. The antimicrobial activities of deer and bovine Lfcin and Lfampin were compared. Based on MIC, deer Lfcin was found to be a more effective inhibitor of ATCC 4356 than bovine Lfcin, but bovine Lfcin and Lfampin were more effective against ATCC 25922 than deer Lfcin and Lfampin. The deer Lfcin sequence differed at seven amino acids from bovine Lfcin and this decreased the net positive charge and increased the hydrophobicity. Deer Lfampin contained two differences in amino acid sequence compared to bovine Lfampin which decreased the net positive charge. These amino acid sequence differences likely account for differences in antibacterial activity. Positive charge and hydrophobic residues provide the amphipathic character of these helical peptides, and are considered important for binding of antimicrobial peptides. In silico modelling of deer Lfcin indicated an identical α-helical structure compared to bovine Lfcin.
尽管对牛乳铁蛋白的生物活性已进行了广泛研究，但关于鹿乳乳铁蛋白的生物活性及其氨基酸序列却知之甚少。本研究调查了鹿乳铁蛋白的氨基酸序列以及两种乳铁蛋白加密肽即乳铁传递素（Lfcin）和乳铁杀菌肽（Lfampin）的抗菌活性。发现鹿乳铁蛋白的分子量为77.1 kDa，等电点为7.99，这与牛乳铁蛋白（78 kDa，pI 7.9）相似。鹿乳铁蛋白含有707个氨基酸，比牛乳铁蛋白少一个氨基酸，与牛乳铁蛋白有92%的同源性。鹿乳铁传递素对美国典型培养物保藏中心（ATCC）25922和ATCC 4356表现出很强的抗菌活性。比较了鹿和牛的Lfcin及Lfampin的抗菌活性。基于最低抑菌浓度（MIC），发现鹿Lfcin对ATCC 4356的抑制作用比牛Lfcin更有效，但牛Lfcin和Lfampin对ATCC 25922的抑制作用比鹿Lfcin和Lfampin更有效。鹿Lfcin序列与牛Lfcin在7个氨基酸处不同，这降低了净正电荷并增加了疏水性。与牛乳铁杀菌肽相比，鹿乳铁杀菌肽的氨基酸序列有两处不同，这降低了净正电荷。这些氨基酸序列差异可能是抗菌活性差异的原因。正电荷和疏水残基赋予了这些螺旋肽两亲性特征，并且被认为对抗菌肽的结合很重要。鹿Lfcin的计算机模拟建模表明其α - 螺旋结构与牛Lfcin相同。
