Rv0050蛋白富脯氨酸区变异对结核分枝杆菌生长分化的影响及调控研究

Control of cell division is a critical part of M. tuberculosis. Bacterial cell growth and division require coordinated cell wall hydrolysis and synthesis, allowing for the removal and expansion of cell wall material. Without proper coordination, unchecked hydrolysis can result in cell lysis. Penicillin-binding protein 1 (PBP1) encoded by Rv0050 is not only a key cell wall synthesizing enzyme but also plays an important role in regulating cell wall hydrolysis. Depletion of the PBP1 results in misshapen bacterial cells and impaired growth. Our study revealed that the repetitive CCG sequence located in the Rv0050 gene exhibited a high polymorphism rate. When allele size was examined between W-Beijing and non-W-Beijing, the comparison revealed that the levels of the locus variation were significantly different between the two groups .Trinucleotide repeating sequences are transcribed into a repeating series of prolines（located in proline-rich domains） in the Rv005 protein sequence. It has been reported that repeating sequences of amino acids can affect the physical and chemical properties of proteins, and harbor the potential for producing gradual and predictable changes in protein action. However, it has been unclear whether repeating sequences of amino acids located in Rv0050 protein can affect the protein function or bacterial phenotype and growth. In this research, we plan to reveal the regulation of bacterial growth and cell division drived by the mutaion of proline-rich domains from Rv0050 protein in mycobacterium tuberculosis. Because cell wall biology is a rich area for antibiotic development, elucidating the mechanisms of essential cell wall processes in mycobacteria offers new avenues for chemotherapy targeted to actively growing or reactivating bacteria.

结核分枝杆菌（MTB）生长分化调控机制的研究对结核病防治有重要意义，同时也是结核病领域需要深入研究的基础科学问题。Rv0050蛋白是MTB肽聚糖合成关键酶，也是细胞壁分化调控机制的核心酶，在细菌生长分化中起重要作用。Rv0050缺失或活性抑制会使细菌形态畸形，生长活性降低甚或溶菌死亡。前期研究显示Rv0050存在多态性富脯氨酸密度区，且多态性具有显著菌株基因型偏向性；构象分析显示该密度区变异很可能影响蛋白的生物学活性。本项目拟在前期工作基础上，利用分子生物学、细菌学、酶学等方法及功能互补实验，进一步研究密度区变异对Rv0050蛋白酶活性、蛋白介导的细胞壁分化调控过程的影响及由此产生的细菌学表型改变，深入揭示密度区变异对MTB生长分化的调控作用。本研究不仅对了解MTB通过变异修饰核心蛋白活性实现对生长分化的调控机制具有重要意义，也可为研发控制细胞分化的抗结核药物及细菌快速培养基提供理论依据。

结核分枝杆菌的生长分化在其对宿主的感染过程中发挥着至关重要的作用，但结核分枝杆菌是如何控制其生长分化的，目前尚需要深入揭示。Rv0050蛋白是结核分枝杆菌肽聚糖合成关键酶，也是细胞壁分化调控机制的核心酶，在细菌的生长分化中起重要作用。我们在前期研究中发现，Rv0050存在多态性的富脯氨酸密度区（PRO-RICH），且多态性具有显著菌株基因型偏向性；构象分析显示该密度区变异很可能影响蛋白的生物学活性。本项目在前期研究的基础上，进一步分析了Rv0050蛋白PRO-RICH变异在结核分枝杆菌生长分化中的功能作用。研究结果显示Rv0050 PRO-RICH变异使不同基因型菌株的生长分化能力发生差异，从而导致产生不同的细菌形态和生长活性，继而影响细菌的毒性和对药物的抗性能力，导致细菌的致病性和应对药物压力的能力发生改变。本研究成果为深入了解MTB的生长分化机制提供了新的理论依据。