Messner Paul, Steiner Kerstin, Zarschler Kristof, Schäffer Christina
Universität für Bodenkultur Wien, Zentrum für NanoBiotechnologie A-1180 Wien, Gregor-Mendel-Strasse 33, Austria.
Carbohydr Res. 2008 Aug 11;343(12):1934-51. doi: 10.1016/j.carres.2007.12.025. Epub 2008 Jan 16.
Cell surface layers (S-layers) are common structures of the bacterial cell envelope with a lattice-like appearance that are formed by a self-assembly process. Frequently, the constituting S-layer proteins are modified with covalently linked glycan chains facing the extracellular environment. S-layer glycoproteins from organisms of the Bacillaceae family possess long, O-glycosidically linked glycans that are composed of a great variety of sugar constituents. The observed variations already exceed the display found in eukaryotic glycoproteins. Recent investigations of the S-layer protein glycosylation process at the molecular level, which has lagged behind the structural studies due to the lack of suitable molecular tools, indicated that the S-layer glycoprotein glycan biosynthesis pathway utilizes different modules of the well-known biosynthesis routes of lipopolysaccharide O-antigens. The genetic information for S-layer glycan biosynthesis is usually present in S-layer glycosylation (slg) gene clusters acting in concert with housekeeping genes. To account for the nanometer-scale cell surface display feature of bacterial S-layer glycosylation, we have coined the neologism 'nanoglycobiology'. It includes structural and biochemical aspects of S-layer glycans as well as molecular data on the machinery underlying the glycosylation event. A key aspect for the full potency of S-layer nanoglycobiology is the unique self-assembly feature of the S-layer protein matrix. Being aware that in many cases the glycan structures associated with a protein are the key to protein function, S-layer protein glycosylation will add a new and valuable component to an 'S-layer based molecular construction kit'. In our long-term research strategy, S-layer nanoglycobiology shall converge with other functional glycosylation systems to produce 'functional' S-layer neoglycoproteins for diverse applications in the fields of nanobiotechnology and vaccine technology. Recent advances in the field of S-layer nanoglycobiology have made our overall strategy a tangible aim of the near future.
细胞表面层（S层）是细菌细胞壁的常见结构，呈晶格状外观，由自组装过程形成。通常，构成S层的蛋白质会被修饰，带有面向细胞外环境的共价连接聚糖链。芽孢杆菌科生物的S层糖蛋白具有长的O-糖苷键连接聚糖，其由多种糖成分组成。观察到的变异已经超过了真核糖蛋白中的表现。由于缺乏合适的分子工具，S层蛋白糖基化过程的分子水平研究落后于结构研究，最近的研究表明，S层糖蛋白聚糖生物合成途径利用了脂多糖O抗原著名生物合成途径的不同模块。S层聚糖生物合成的遗传信息通常存在于与管家基因协同作用的S层糖基化（slg）基因簇中。为了解释细菌S层糖基化的纳米级细胞表面展示特征，我们创造了新词“纳米糖生物学”。它包括S层聚糖的结构和生化方面以及糖基化事件背后机制的分子数据。S层纳米糖生物学充分发挥效力的一个关键方面是S层蛋白质基质独特的自组装特征。意识到在许多情况下，与蛋白质相关的聚糖结构是蛋白质功能的关键，S层蛋白糖基化将为“基于S层的分子构建工具包”增添一个新的有价值的组成部分。在我们的长期研究策略中，S层纳米糖生物学应与其他功能性糖基化系统相结合，以生产用于纳米生物技术和疫苗技术领域各种应用的“功能性”S层新糖蛋白。S层纳米糖生物学领域的最新进展使我们的总体策略成为不久将来的一个切实目标。
