中文摘要：噬菌体内溶素（细胞裂解酶或胞壁质水解酶）是噬菌体用来降解细胞壁肽聚糖（PG）并随后从内部分解细菌细胞的酶。细胞裂解酶因其溶壁活性，被认为是对抗抗生素耐药性的潜在候选。然而，大多数天然形式的细胞裂解酶缺乏侵入革兰氏阴性（G-ve）细菌外膜（OM）的能力。为了将噬菌体酶转化为对抗G-ve细菌的抗菌武器，赋予这些酶进入OM后方PG底物的能力至关重要。研究表明在溶壁酶LysAB2的C-末端融合膜通透性肽CeA可实现两步杀灭细菌，并将LysAB2抗耐多药鲍曼不动杆菌的活性提高100000倍。工程化的LysAB2，这里称为LysAB2-KWIC，在固定相对鲍曼不动杆菌也显示出显著的活性，并且具有显著的破坏生物膜形成的能力。此外，该酶对G-ve菌具有广泛的抗菌谱，对血清有良好的耐受性，且耐贮存。LysAB2-KVJK通过系统给药可拯救鲍曼不动杆菌感染的大蜡螟幼虫。总之，本研究使球状细胞裂解酶具有OM通透性活性，能够有效杀灭G-ve细菌，揭示了球状细胞裂解酶C-端在抗菌活性中的关键作用，并指出了一条可行的途径，将球状细胞裂解酶作为抗菌酶，用于临床治疗耐多药的G-ve细菌。
外文摘要：Bacteriophage endolysins (lysins, or murein hydrolases) are enzymes that bacteriophages utilize to degrade the cell wall peptidoglycans (PG) and subsequently disintegrate bacterial cells from within. Due to their muralytic activity, lysins are considered as potential candidates to battle against antibiotic resistance. However, most lysins in their native form lack the capability of trespassing the outer membrane (OM) of Gram-negative (G-ve) bacteria. To turn the bacteriophage enzymes into antibacterial weapons against G-ve bacteria, endowing these enzymes the capability of accessing the PG substrate underneath the OM is critical. Here we show that fusing a membrane-permeabilizing peptide CeA at the C-terminus of a muralytic enzyme LysAB2 renders a two-step mechanism of bacterial killing and increases the activity of LysAB2 against the multidrug resistant Acinetobacter baumannii by up to 100 000-folds. The engineered LysAB2, termed LysAB2-KWIC here, also shows remarkable activity against A. baumannii at the stationary phase and a prominent capability to disrupt biofilm formation. In addition, the enzyme shows a broad antibacterial spectrum against G-ve bacteria, a decent tolerance to serum, and a prolonged storage life. LysAB2-KVJK rescues the larva of the greater wax moth Galleria mellonella from A. baumannii infection through systemic administration. Altogether, our work equips a globular lysin with OM permeabilization activity to enable effective killing of G-ve bacteria, reveals the critical role of the C-terminus of a globular lysin in the antibacterial activity, and points toward a viable route to engineer globular lysins as antibacterial enzymes for potential clinical use against multidrug resistant G-ve bacteria.
外文关键词：endolysin；Gram-negative bacteria；Acinetobacter Baumannii；antibacterial；outer membrane
作者：Chen, X；Liu, M；Zhang, PF；Leung, SSY；Xia, J
作者单位：Chinese Univ Hong Kong
期刊名称：ACS INFECTIOUS DISEASES
期刊影响因子：4.614
出版年份：2021
出版刊次：8
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