Meeting Abstract

132-7  Sunday, Jan. 7 15:00 – 15:15  Between the Melanin Nanosheets with a Naked Polychaete WONDERLY, W.R.*; DEMARTINI, D.G.; MONNIER, C.A.; WAITE, J.H.; University of California, Santa Barbara; University of California, Santa Barbara; University of California, Santa Barbara; University of California, Santa Barbara wwonderly@chem.ucsb.edu

Nature utilizes a variety of chemistries in order to generate hardened materials. One curious example is Glycera dibranchiata, a burrowing intertidal sandworm that utilizes four black, venom-injecting jaws to grasp and attack its prey. The composition of these jaws has been shown to be approximately 50% protein, 10% copper (in mineralized and ionic form), and, surprisingly, 40% melanin. However, because these jaws are highly sclerotized, the only previous characterization of the protein component has been amino acid analysis, which has indicated a striking composition of >50% glycine and >30% histidine. In this study we have utilized next generation sequencing to identify a 23kDa protein fitting this composition. We show that this protein binds a large amount of copper (20 Cu atoms per protein) with high affinity, and that the copper-bound protein complex exhibits catechol oxidase activity toward 3,4-dihydroxy-L-phenylalanine. Finally, using scanning electron microscopy and atomic force microscopy we have identified the product of this catalysis to be synthetic melanin sheets with a thickness of ~45 Å with a very large surface area. Understanding the multifunctionality of this protein (metal binding, catalysis, and scaffolding) will allow unprecedented control over the morphology of a biopolymer that is notoriously complex and opens the door to many engineering applications.