PDF(Pubmed)
Abstract：
Filamentous growth of streptomycetes coincides with the synthesis and deposition of an uncharacterized protective glucan at hyphal tips. Synthesis of this glucan depends on the integral membrane protein CslA and the radical copper oxidase GlxA, which are part of a presumably large multiprotein complex operating at growing tips. Here, we show that CslA and GlxA interact by forming a protein complex that is sufficient to synthesize cellulose in vitro. Mass spectrometry analysis revealed that the purified complex produces cellulose chains with a degree of polymerization of at least 80 residues. Truncation analyses demonstrated that the removal of a significant extracellular segment of GlxA had no impact on complex formation, but significantly diminished activity of CslA. Altogether, our work demonstrates that CslA and GlxA form the active core of the cellulose synthase complex and provide molecular insights into a unique cellulose biosynthesis system that is conserved in streptomycetes.
OBJECTIVE: Cellulose stands out as the most abundant polysaccharide on Earth. While the synthesis of this polysaccharide has been extensively studied in plants and Gram-negative bacteria, the mechanisms in Gram-positive bacteria have remained largely unknown. Our research unveils a novel cellulose synthase complex formed by the interaction between the cellulose synthase-like protein CslA and the radical copper oxidase GlxA from Streptomyces lividans, a soil-dwelling Gram-positive bacterium. This discovery provides molecular insights into the distinctive cellulose biosynthesis machinery. Beyond expanding our understanding of cellulose biosynthesis, this study also opens avenues for exploring biotechnological applications and ecological roles of cellulose in Gram-positive bacteria, thereby contributing to the broader field of microbial cellulose biosynthesis and biofilm research.
OBJECTIVE: Cellulose stands out as the most abundant polysaccharide on Earth. While the synthesis of this polysaccharide has been extensively studied in plants and Gram-negative bacteria, the mechanisms in Gram-positive bacteria have remained largely unknown. Our research unveils a novel cellulose synthase complex formed by the interaction between the cellulose synthase-like protein CslA and the radical copper oxidase GlxA from Streptomyces lividans, a soil-dwelling Gram-positive bacterium. This discovery provides molecular insights into the distinctive cellulose biosynthesis machinery. Beyond expanding our understanding of cellulose biosynthesis, this study also opens avenues for exploring biotechnological applications and ecological roles of cellulose in Gram-positive bacteria, thereby contributing to the broader field of microbial cellulose biosynthesis and biofilm research.
摘要：
链霉菌的丝状生长与菌丝顶端未表征的保护性葡聚糖的合成和沉积一致。这种葡聚糖的合成取决于完整的膜蛋白CslA和自由基铜氧化酶GlxA，它们可能是在生长尖端运行的大型多蛋白复合物的一部分。这里,我们显示CslA和GlxA通过形成足以在体外合成纤维素的蛋白质复合物而相互作用。质谱分析显示,纯化的复合物产生聚合度为至少80个残基的纤维素链。截短分析表明，去除明显的GlxA细胞外段对复合物的形成没有影响，但CSLA的活性显著降低。总之,我们的工作表明，CslA和GlxA形成了纤维素合酶复合物的活性核心，并提供了对链霉菌中保守的独特纤维素生物合成系统的分子见解。
目的：纤维素是地球上最丰富的多糖。虽然这种多糖的合成已经在植物和革兰氏阴性菌中得到了广泛的研究,革兰氏阳性细菌的机制在很大程度上仍然未知.我们的研究揭示了一种新型的纤维素合酶复合物，该复合物由纤维素合酶样蛋白CslA和来自绿链霉菌的自由基铜氧化酶GlxA之间的相互作用形成，一种居住在土壤中的革兰氏阳性细菌。这一发现为独特的纤维素生物合成机制提供了分子见解。除了扩大我们对纤维素生物合成的理解，这项研究还为探索纤维素在革兰氏阳性细菌中的生物技术应用和生态作用开辟了道路，从而有助于微生物纤维素生物合成和生物膜研究的更广阔领域。
目的：纤维素是地球上最丰富的多糖。虽然这种多糖的合成已经在植物和革兰氏阴性菌中得到了广泛的研究,革兰氏阳性细菌的机制在很大程度上仍然未知.我们的研究揭示了一种新型的纤维素合酶复合物，该复合物由纤维素合酶样蛋白CslA和来自绿链霉菌的自由基铜氧化酶GlxA之间的相互作用形成，一种居住在土壤中的革兰氏阳性细菌。这一发现为独特的纤维素生物合成机制提供了分子见解。除了扩大我们对纤维素生物合成的理解，这项研究还为探索纤维素在革兰氏阳性细菌中的生物技术应用和生态作用开辟了道路，从而有助于微生物纤维素生物合成和生物膜研究的更广阔领域。
