Liang Chao, Li Yunqiu, Liu Zhiming, Wu Wenjian, Hu Biru
Department of Chemistry and Biology, College of Science, National University of Defense Technology, Changsha, Hunan, China.
Department of Chemistry and Biology, College of Science, National University of Defense Technology, Changsha, Hunan, China; State Key Laboratory of NBC Protection for Civilian, Beijing, China.
PLoS One. 2015 Aug 28;10(8):e0136493. doi: 10.1371/journal.pone.0136493. eCollection 2015.
The barnacle is well known for its tenacious and permanent attachment to a wide variety of underwater substrates, which is accomplished by synthesizing, secreting and curing a mixture of adhesive proteins termed "barnacle cement". In order to evaluate interfacial adhesion abilities of barnacle cement proteins, the cp19k homologous gene in Balanus albicostatus (Balcp19k) was cloned and expressed in Escherichia coli. Here, we report an intriguing discovery of a gel-like super adhesive aggregation produced by Trx-Balcp19k, a recombinant Balcp19k fusion protein. The Trx-Balcp19k consists of an 18 kDa fragment at the N-terminus, which is encoded by pET-32a(+) plasmid and mainly comprised of a thioredoxin (Trx) tag, and Balcp19k at the C-terminus. The sticky aggregation was designated as "Trx-Balcp19k gel", and the bulk adhesion strength, biochemical composition, as well as formation conditions were all carefully investigated. The Trx-Balcp19k gel exhibited strong adhesion strength of 2.10 ± 0.67 MPa, which was approximately fifty folds higher than that of the disaggregated Trx-Balcp19k (40 ± 8 kPa) and rivaled those of commercial polyvinyl acetate (PVA) craft glue (Mont Marte, Australia) and UHU glue (UHU GmbH & Co. KG, Germany). Lipids were absent from the Trx-Balcp19k gel and only a trace amount of carbohydrates was detected. We postulate that the electrostatic interactions play a key role in the formation of Trx-Balcp19k gel, by mediating self-aggregation of Trx-Balcp19k based on its asymmetric distribution pattern of charged amino acids. Taken together, we believe that our discovery not only presents a promising biological adhesive with potential applications in both biomedical and technical fields, but also provides valuable paradigms for molecular design of bio-inspired peptide- or protein-based materials.
藤壶以其对各种水下基质的顽强且持久的附着而闻名，这是通过合成、分泌和固化一种称为“藤壶胶”的粘附蛋白混合物来实现的。为了评估藤壶胶蛋白的界面粘附能力，在白脊藤壶（Balcp19k）中克隆了cp19k同源基因并在大肠杆菌中表达。在此，我们报告了由重组Balcp19k融合蛋白Trx-Balcp19k产生的凝胶状超级粘附聚集体的有趣发现。Trx-Balcp19k在N端由一个18 kDa的片段组成，该片段由pET-32a(+)质粒编码，主要由硫氧还蛋白（Trx）标签组成，C端为Balcp19k。这种粘性聚集体被命名为“Trx-Balcp19k凝胶”，并对其整体粘附强度、生化组成以及形成条件进行了仔细研究。Trx-Balcp19k凝胶表现出2.10±0.67 MPa的强粘附强度，比未聚集的Trx-Balcp19k（40±8 kPa）高出约五十倍，与商业聚醋酸乙烯酯（PVA）工艺胶（澳大利亚蒙特马特尔）和UHU胶（德国UHU GmbH & Co. KG）相当。Trx-Balcp19k凝胶中不存在脂质，仅检测到微量碳水化合物。我们推测静电相互作用在Trx-Balcp19k凝胶的形成中起关键作用，通过基于其带电氨基酸的不对称分布模式介导Trx-Balcp19k的自聚集。综上所述，我们认为我们的发现不仅提出了一种在生物医学和技术领域都有潜在应用前景的有前途的生物粘合剂，而且为基于生物启发的肽或蛋白质材料的分子设计提供了有价值的范例。
