Sijbrandij Tjitske, Ligtenberg Antoon J, Nazmi Kamran, Veerman Enno C I, Bolscher Jan G M, Bikker Floris J
Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, 1081 LA, Amsterdam, The Netherlands.
World J Microbiol Biotechnol. 2017 Jan;33(1):3. doi: 10.1007/s11274-016-2171-8. Epub 2016 Nov 10.
Lactoferrin (LF) is an important immune protein in neutrophils and secretory fluids of mammals. Bovine LF (bLF) harbours two antimicrobial stretches, lactoferricin and lactoferampin, situated in close proximity in the N1 domain. To mimic these antimicrobial domain parts a chimeric peptide (LFchimera) has been constructed comprising parts of both stretches (LFcin17-30 and LFampin265-284). To investigate the potency of this construct to combat a set of Gram positive and Gram negative bacteria which are regarded as simulants for biological warfare agents, the effect on bacterial killing, membrane permeability and membrane polarity were determined in comparison to the constituent peptides and the native bLF. Furthermore we aimed to increase the antimicrobial potency of the bLF derived peptides by cationic amino acid substitutions. Overall, the bactericidal activity of the peptides could be related to membrane disturbing effects, i.e. membrane permeabilization and depolarization. Those effects were most prominent for the LFchimera. Arginine residues were found to be crucial for displaying antimicrobial activity, as lysine to arginine substitutions resulted in an increased antimicrobial activity, affecting mostly LFampin265-284 whereas arginine to lysine substitutions resulted in a decreased bactericidal activity, predominantly in case of LFcin17-30.
乳铁蛋白（LF）是哺乳动物中性粒细胞和分泌液中的一种重要免疫蛋白。牛乳铁蛋白（bLF）在N1结构域中紧邻的位置含有两个抗菌片段，即乳铁素和乳铁杀菌肽。为了模拟这些抗菌结构域部分，构建了一种嵌合肽（LFchimera），其包含两个片段（LFcin17 - 30和LFampin265 - 284）的部分序列。为了研究该构建体对抗一组被视为生物战剂模拟物的革兰氏阳性菌和革兰氏阴性菌的效力，与组成肽和天然bLF相比，测定了其对细菌杀伤、膜通透性和膜极性的影响。此外，我们旨在通过阳离子氨基酸取代来提高bLF衍生肽的抗菌效力。总体而言，这些肽的杀菌活性可能与膜干扰效应有关，即膜通透性增加和去极化。这些效应在LFchimera中最为显著。发现精氨酸残基对于发挥抗菌活性至关重要，因为赖氨酸替换为精氨酸会导致抗菌活性增加，主要影响LFampin265 - 284，而精氨酸替换为赖氨酸则会导致杀菌活性降低，主要发生在LFcin17 - 30的情况下。
