Comparative Analysis of the Adhesive Proteins of the Adult Stalked Goose Barnacle Pollicipes pollicipes (Cirripedia: Pedunculata)
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Adhesion in barnacles is still poorly understood. The cement gland secretes an insoluble multi-protein complex, which adheres very strongly to a variety of substrates in the presence of water. This adhesion mechanism is bioinspiring for the engineering of new adhesive materials, but to replicate this adhesive system, the genes coding for the cement constitutive proteins must be identified and elucidated, and their products characterised. Here, the complete sequences of three cement protein (CP) genes (CP-100K, CP-52K, and CP-19K) isolated from the cement gland of the stalked barnacle Pollicipes pollicipes (order Scalpelliformes) were obtained using RACE PCR. The three genes were compared to the 23 other acorn barnacle CP genes so far sequenced (order Sessilia) to determine common and differential patterns and molecular properties, since the adhesives of both orders have visibly different characteristics. A shotgun proteomic analysis was performed on the cement, excreted at the membranous base of specimens, where the products of the three genes sequenced in the gland were identified, validating their function as CPs. A principal component analysis (PCA) was performed, to cluster CPs into groups with similar amino acid composition. This analysis uncovered three CP groups, each characterised by similar residue composition, features in secondary structure, and some biochemical properties, including isoelectric point and residue accessibility to solvents. The similarity among proteins in each defined group was low despite comparable amino acid composition. PCA can identify putative adhesive proteins from NGS transcriptomic data regardless of their low homology. This analysis did not highlight significant differences in residue composition between homologous acorn and stalked barnacle CPs. The characteristics responsible for the structural differences between the cement of stalked and acorn barnacles are described, and the presence of nanostructures, such as repetitive homologous domains and low complexity regions, and repetitive β-sheets are discussed relatively to self-assembly and adhesion.
KeywordsAdhesive proteins Cement proteins Biased residue composition Adult barnacle Interface surface adhesion Underwater adhesion
This research was partially supported by the Structured Program of R&D&I INNOVMAR – Innovation and Sustainability in the Management and Exploitation of Marine Resources (reference NORTE-01-0145-FEDER-000035, Research Line NOVELMAR), funded by the Northern Regional Operational Programme (NORTE2020) through the European Regional Development Fund (ERDF). The research was also funded by the Portuguese Foundation for Science and Technology (FCT) through the strategic project “UID/Multi/04423/2013” and a postdoctoral fellowship to IC (SFRH/BPD/110020/2015) and AC (SFRH/BPD/103683/2014).
Compliance with Ethical Standards
All authors have disclosed any actual or potential competing interests (financial or non-financial) regarding the content of this article. All experiments were conducted in accordance with ethical guidelines of the European Union Council (Directives 86/609/EEC and 2010/63/EU) and the Portuguese Agricultural Ministry (Portaria nr.1005/92 of 23 October 2010) for the protection of animals used for experimental and other scientific purposes.
Conflict of Interest
The authors declare that they have no conflict of interest.
- Anderson DT (1994) Reproductive system, mating and oviposition. In: Anderson DT (ed) Barnacles. Structure, function, development and evolution, 1st edn. Chapman & Hall, London, pp 127–170Google Scholar
- Cejas MA, Kinney WA, Chen C, Vinter JG, Almond HR, Balss KM, Maryanoff CA, Schmidt U, Breslav M, Mahan A, Lacy E, Maryanoff BE (2008) Thrombogenic collagen-mimetic peptides: self-assembly of triple helix-based fibrils driven by hydrophobic interactions. Proc Natl Acad Sci U S A 105:8513–8518CrossRefGoogle Scholar
- Cui M, Ren S, Wei S, Sun C, Zhong C (2017) Natural and bio-inspired underwater adhesives. Curr Prog New Persp 5(11):116102Google Scholar
- He LS, Zhang G, Qian PY (2013) FG-rich repeats of nuclear pore proteins form a three-dimensional meshwork with hydrogel-like properties. PLoS One 8:1–9Google Scholar
- Moriarty JE, Sachs JA, Jones K (2008) Directional locomotion in a turtle barnacle, Chelonibia testudinaria, on green turtles, Chelonia mydas. Mar Turt Newsl 119:1–4Google Scholar
- OSPAR (2008) OSPAR list of threatened and/or declining species and habitats (agreement 2008–6). OSPAR CommGoogle Scholar
- Power AM, Klepal W, Zheden V, Jonker J, Mcevilly P, von Byern J (2010) Mechanisms of Adhesion in Adult Barnacles. In: von Byern J, Grunwald I (eds) Biological Adhesive Systems. Springer, ViennaGoogle Scholar
- Yule AB, Walker G (1987) Adhesion in barnacles. In: Crustacean Issues: Barnacle Biology, vol 5. Balkema, pp 389–402Google Scholar
- Zheden V, Klepal W, Gorb SN, Kovalev A (2014a) Mechanical properties of the cement of the stalked barnacle dosima fascicularis (cirripedia, crustacea). Interface Focus 5:1–9Google Scholar