Subedi Bishwa P, Martin William F, Carbone Vincenzo, Duin Eduardus C, Cronin Bryan, Sauter Julia, Schofield Linley R, Sutherland-Smith Andrew J, Ronimus Ron S
AgResearch Ltd. Grasslands, Tennent Drive, Palmerston North 4442, New Zealand.
Massey University, Tennent Drive, Palmerston North 4442, New Zealand.
FEMS Microbes. 2021 Aug 24;2:xtab012. doi: 10.1093/femsmc/xtab012. eCollection 2021.
Bacteria near-universally contain a cell wall sacculus of murein (peptidoglycan), the synthesis of which has been intensively studied for over 50 years. In striking contrast, archaeal species possess a variety of other cell wall types, none of them closely resembling murein. Interestingly though, one type of archaeal cell wall termed pseudomurein found in the methanogen orders Methanobacteriales and Methanopyrales is a structural analogue of murein in that it contains a glycan backbone that is cross-linked by a L-amino acid peptide. Here, we present taxonomic distribution, gene cluster and phylogenetic analyses that confirm orthologues of 13 bacterial murein biosynthesis enzymes in pseudomurein-containing methanogens, most of which are distantly related to their bacterial counterparts. We also present the first structure of an archaeal pseudomurein peptide ligase from DSM1088 (Mfer336) to a resolution of 2.5 Å and show that it possesses a similar overall tertiary three domain structure to bacterial MurC and MurD type murein peptide ligases. Taken together the data strongly indicate that murein and pseudomurein biosynthetic pathways share a common evolutionary history.
细菌几乎普遍含有一层由胞壁质（肽聚糖）构成的细胞壁囊泡，其合成过程已被深入研究了50多年。与之形成鲜明对比的是，古菌物种拥有多种其他类型的细胞壁，没有一种与胞壁质非常相似。不过，有趣的是，在甲烷杆菌目和甲烷火菌目中发现的一种被称为假胞壁质的古菌细胞壁类型是胞壁质的结构类似物，因为它含有一个由L - 氨基酸肽交联的聚糖主链。在此，我们展示了分类分布、基因簇和系统发育分析，这些分析证实了含假胞壁质的产甲烷菌中13种细菌胞壁质生物合成酶的直系同源物，其中大多数与它们的细菌对应物关系较远。我们还展示了来自DSM1088（Mfer336）的古菌假胞壁质肽连接酶的首个结构，分辨率为2.5 Å，并表明它具有与细菌MurC和MurD型胞壁质肽连接酶相似的整体三级三结构域结构。综合这些数据有力地表明，胞壁质和假胞壁质生物合成途径有着共同的进化历史。
