title: Protein Aggregation Formed by Recombinant cp19k Homologue of Balanus albicostatus Combined with an 18 kDa N-Terminus Encoded by pET-32a(+) Plasmid Having Adhesion Strength Comparable to Several Commercial Glues.
abstract: 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.
authors: Department of Chemistry and Biology, College of Science, National University of Defense Technology, Changsha, Hunan, China.
authors: Chao
authors: C
authors: Liang
authors: Department of Chemistry and Biology, College of Science, National University of Defense Technology, Changsha, Hunan, China.
authors: Yunqiu
authors: Y
authors: Li
authors: Department of Chemistry and Biology, College of Science, National University of Defense Technology, Changsha, Hunan, China.
authors: Zhiming
authors: Z
authors: Liu
authors: 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.
authors: Wenjian
authors: W
authors: Wu
authors: Department of Chemistry and Biology, College of Science, National University of Defense Technology, Changsha, Hunan, China.
authors: Biru
authors: B
authors: Hu
mesh_terms: D000269:Adhesives / Q000737:chemistry*; D000818:Animals; D060829:Arthropod Proteins / Q000737:chemistry* / Q000235:genetics; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics; D010957:Plasmids; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D001468:Thoracica / Q000737:chemistry* / Q000235:genetics
chemical_list: D000269:Adhesives; D060829:Arthropod Proteins; D011994:Recombinant Proteins