Research Institute for Physico-Chemical Medicine of the Federal Medical-Biological Agency of Russia, Moscow, Malaya Pirogovskaya St. 1a, Moscow 119435, Russia.
J Bacteriol. 2011 Sep;193(18):4943-53. doi: 10.1128/JB.05059-11. Epub 2011 Jul 22.
We present the complete genome sequence and proteogenomic map for Acholeplasma laidlawii PG-8A (class Mollicutes, order Acholeplasmatales, family Acholeplasmataceae). The genome of A. laidlawii is represented by a single 1,496,992-bp circular chromosome with an average G+C content of 31 mol%. This is the longest genome among the Mollicutes with a known nucleotide sequence. It contains genes of polymerase type I, SOS response, and signal transduction systems, as well as RNA regulatory elements, riboswitches, and T boxes. This demonstrates a significant capability for the regulation of gene expression and mutagenic response to stress. Acholeplasma laidlawii and phytoplasmas are the only Mollicutes known to use the universal genetic code, in which UGA is a stop codon. Within the Mollicutes group, only the sterol-nonrequiring Acholeplasma has the capacity to synthesize saturated fatty acids de novo. Proteomic data were used in the primary annotation of the genome, validating expression of many predicted proteins. We also detected posttranslational modifications of A. laidlawii proteins: phosphorylation and acylation. Seventy-four candidate phosphorylated proteins were found: 16 candidates are proteins unique to A. laidlawii, and 11 of them are surface-anchored or integral membrane proteins, which implies the presence of active signaling pathways. Among 20 acylated proteins, 14 contained palmitic chains, and six contained stearic chains. No residue of linoleic or oleic acid was observed. Acylated proteins were components of mainly sugar and inorganic ion transport systems and were surface-anchored proteins with unknown functions.
我们呈现了 Acholeplasma laidlawii PG-8A（类柔膜体纲，支原体目，柔膜体科）的完整基因组序列和蛋白质基因组图谱。A. laidlawii 的基因组由一条 1,496,992bp 的圆形染色体组成，平均 G+C 含量为 31mol%。这是已知核苷酸序列的柔膜体纲中最长的基因组。它包含聚合酶 I、SOS 反应和信号转导系统的基因，以及 RNA 调节元件、核糖开关和 T 盒。这表明其具有显著的基因表达调控和对压力的突变响应能力。A. laidlawii 和植原体是已知唯一使用通用遗传密码的柔膜体纲，其中 UGA 是一个终止密码子。在柔膜体纲中，只有非固醇要求的 Acholeplasma 才有从头合成饱和脂肪酸的能力。蛋白质组学数据用于基因组的初步注释，验证了许多预测蛋白的表达。我们还检测到 A. laidlawii 蛋白的翻译后修饰：磷酸化和酰化。发现了 74 个候选磷酸化蛋白：16 个候选蛋白是 A. laidlawii 特有的，其中 11 个是表面锚定或整合膜蛋白，这表明存在活跃的信号通路。在 20 个酰化蛋白中，有 14 个含有棕榈酸链，6 个含有硬脂酸链。没有观察到亚油酸或油酸残基。酰化蛋白是主要的糖和无机离子运输系统的组成部分，是具有未知功能的表面锚定蛋白。
