Formation of Gold Particles via Thiol Groups on Glycoconjugates Comprising the Sheath Skeleton of Leptothrix
Formation of Gold Particles via Thiol Groups on Glycoconjugates Comprising the Sheath Skeleton of Leptothrix
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DOI：
10.1080/01490451.2018.1550127
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发表时间：
2019-01
影响因子：
2.3
通讯作者：
T. Kunoh;Y. Kusano;M. Takeda;M. Nakanishi;S. Matsumoto;I. Suzuki;M. Takano;H. Kunoh;J. Takada
中科院分区：
文献类型：
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作者：
T. Kunoh;Y. Kusano;M. Takeda;M. Nakanishi;S. Matsumoto;I. Suzuki;M. Takano;H. Kunoh;J. Takada
细螺旋体是一种铁氧化细菌，其产生的微管鞘围绕着链状细胞。从细胞表面排出的有机纳米原纤维相互交织、结合形成未成熟的鞘，并吸引水相无机物最终形成成熟的有机-无机鞘。鞘的这种无机结壳是鞘骨架中官能团与无机物相互作用的结果。根据我们之前的研究结果，细钩绦虫鞘骨架吸附了47种无机物（Au是最丰富的吸附剂之一），我们检查了Au阳离子在细胞包膜鞘及其无蛋白残余物上的吸附状态，发现纳米到亚微米的Au颗粒（分别为AuNPs和AuSMPs）在由糖缀合物（一种由半胱氨酸、甘氨酸和3-羟基丙酸修饰的两性聚糖）组成的鞘形成聚合物上形成。当纯化后的聚合物在HAuCl4溶液中孵育时，在聚合物表面形成AuNPs和AuSMPs。在HAuCl4溶液中，这两种颗粒也在包膜鞘和无蛋白鞘残体上形成。当用荧光蛋白掩盖包裹细胞鞘中的SH基团时，在HAuCl4溶液中孵育后不形成Au颗粒。结果表明，SH基团至少部分参与了Au阳离子还原为金属Au和最终形成Au颗粒的过程。
Abstract Leptothrix, iron-oxidizing bacterium, produces microtubular sheaths that surround the catenulate cells. Organic nanofibrils excreted from the cell surfaces interweave and coalesce to form immature sheaths, which attract aqueous-phase inorganics to eventually form mature organic–inorganic sheaths. Such inorganic encrustation of the sheaths results from interactions between functional groups in the sheath skeleton and inorganics. Based on our previous findings that Leptothrix sheath skeleton sorbed 47 inorganics (Au was one of the most abundant adsorbates), we examined the sorption status of Au cations on cell-enclosing sheaths and their protein-free remnants and found that nano to sub-micron Au particles (AuNPs and AuSMPs, respectively) formed on the sheath-forming polymer consisting of a glycoconjugate (an amphoteric glycan modified with cysteine, glycine, and 3-hydroxypropionic acid). When the purified polymer was incubated in HAuCl4 solution, AuNPs and AuSMPs formed on the polymer surfaces. Both particles formed also on cell-enclosing sheaths and protein-free sheath remnants incubated in HAuCl4 solution. When SH groups in the cell-enclosing sheaths were masked with a fluorescent protein, Au particles did not form after incubation in HAuCl4 solution. Results implicate that SH groups are at least partially involved in the reduction of Au cations to metallic Au and eventual formation of Au particles.