Whitney John C, Peterson S Brook, Kim Jungyun, Pazos Manuel, Verster Adrian J, Radey Matthew C, Kulasekara Hemantha D, Ching Mary Q, Bullen Nathan P, Bryant Diane, Goo Young Ah, Surette Michael G, Borenstein Elhanan, Vollmer Waldemar, Mougous Joseph D
Department of Microbiology, University of Washington School of Medicine, Seattle, United States.
Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle, United Kingdom.
Elife. 2017 Jul 11;6:e26938. doi: 10.7554/eLife.26938.
The Firmicutes are a phylum of bacteria that dominate numerous polymicrobial habitats of importance to human health and industry. Although these communities are often densely colonized, a broadly distributed contact-dependent mechanism of interbacterial antagonism utilized by Firmicutes has not been elucidated. Here we show that proteins belonging to the LXG polymorphic toxin family present in mediate cell contact- and Esx secretion pathway-dependent growth inhibition of diverse Firmicute species. The structure of one such toxin revealed a previously unobserved protein fold that we demonstrate directs the degradation of a uniquely bacterial molecule required for cell wall biosynthesis, lipid II. Consistent with our functional data linking LXG toxins to interbacterial interactions in , we show that LXG genes are prevalent in the human gut microbiome, a polymicrobial community dominated by Firmicutes. We speculate that interbacterial antagonism mediated by LXG toxins plays a critical role in shaping Firmicute-rich bacterial communities.
厚壁菌门是一类细菌，在许多对人类健康和工业具有重要意义的多微生物栖息地中占主导地位。尽管这些群落通常被大量定殖，但厚壁菌门所利用的一种广泛分布的细菌间接触依赖性拮抗机制尚未阐明。在这里，我们表明，存在于 中的属于LXG多态毒素家族的蛋白质介导了不同厚壁菌门物种的细胞接触和Esx分泌途径依赖性生长抑制。一种这样的毒素的结构揭示了一种以前未观察到的蛋白质折叠，我们证明它指导了细胞壁生物合成所需的一种独特细菌分子脂质II的降解。与我们将LXG毒素与 中的细菌间相互作用联系起来的功能数据一致，我们表明LXG基因在人类肠道微生物群中普遍存在，人类肠道微生物群是一个以厚壁菌门为主导的多微生物群落。我们推测，由LXG毒素介导的细菌间拮抗作用在塑造富含厚壁菌门的细菌群落中起关键作用。
