Significance of the conformation of building blocks in curing of barnacle underwater adhesive

Abstract

Barnacles are a unique sessile crustacean that attach irreversibly and firmly to foreign underwater surfaces. Its biological underwater adhesive is a peculiar extracellular multi‐protein complex. Here we characterize one of the two major proteins, a 52 kDa protein found in the barnacle cement complex. Cloning of the cDNA revealed that the protein has no homolog in the nonredundant database. The primary structure consists of four long sequence repeats. The process of dissolving the protein at the adhesive joint of the animal by various treatments was monitored in order to obtain insight into the molecular mechanism involved in curing of the adhesive bulk. Treatments with protein denaturant, reducing agents and/or chemical‐specific proteolysis in combination with 2D diagonal PAGE indicated no involvement of the protein in intermolecular cross‐linkage/polymerization, including formation of intermolecular disulfide bonds. As solubilization of the proteins required high concentrations of denaturing agents, it appears that both the conformation of the protein as building blocks and non‐covalent molecular interactions between the building blocks, possibly hydrophobic interactions and hydrogen bonds, are crucial for curing of the cement. It was also suggested that the protein contributes to surface coupling by an anchoring effect to micro‐ to nanoscopic roughness of surfaces. Database Sequence of Megabalanus rosa cp52k mRNA for 52 kDa cement protein has been submitted to the DNA Data Bank of Japan under accession number http://www.ncbi.nlm.nih.gov/nuccore/AB623048.

Biochemical analyses of the cement float of the goose barnacleDosima fascicularis– a preliminary study

“…The high amounts of hydrophobic amino acids found in the cement of D. fascicularis agree with the findings in the cement of B. crenatus, B. perforatus and M. rosa. Naldrett & Kaplan (1997), Kamino (2010) and Kamino et al (2012) stated that hydrophobic interactions rendered the cement matrix insoluble and made it resistant to decomposition by Biofouling 959 marine bacteria (Naldrett 1993). Both qualities are particularly important for Dosima cement because the cement needs stability against mechanical impact while drifting in the sea (Zheden et al unpublished).…”

Profiling of adhesive-related genes in the freshwater cnidarianHydra magnipapillataby transcriptomics and proteomics

“…The presence of glycans in the adhesive secretory granules of Hydra has been reported Rodrigues et al (Forthcoming). Several adhesive proteins performing either permanent or temporary adhesion have been found to be glycosylated in other systems, such as in the marine sea stars, barnacles and green mussels (Ohkawa et al 2004; Zhao et al 2009; Hennebert et al 2010; Kamino et al 2012), in freshwater zebra mussels (Rzepecki & Waite 1993), and also in the stick threads secreted by terrestrial velvet worms (Graham et al 2013). Both N- and O-glycosylation were reported, as is the case of N-glycosylation of cp52 k in barnacles, and O-linked glycans primarily to threonine residues in green and zebra mussels Pvfp-1 and Dpfp-1 (Rzepecki & Waite 1993; Ohkawa et al 2004; Zhao et al 2009).…”

Growth and development of the barnacleAmphibalanus amphitrite: time and spatially resolved structure and chemistry of the base plate

“…The spectral features observed by FTIR and XPS are consistent with proteinaceous chemistries. There are multiple proteins associated with the cuticle of Crustacea, including settlement inducing proteins in barnacles (Dreanno et al 2006), but the specific components that could be related to prior biochemical assays of barnacles (Kamino et al 2012), and their relationship to the cuticle membrane, have yet to be identified.…”