Lustrin A

Lustrin A is an insoluble protein used in the production of a nacreous layer in bivalve molluscs.^[1] It contributes to the properties of the nacreous layer, imparting resistance to cracking and elasticity.^[2] This is accomplished by its structure; it consists of many spring-like units which can expand when the shell is under extensional pressure.^[3] Its structure is similar to that of proteins involved in silica deposition in diatoms.^[1] It consists of 1428 amino acid residues. Its molecular weight is estimated to be 142 kDa. Its terminus consists of a protease inhibitor, which contributes to its longevity in the molluscan shell matrix.^[3]