title: Presence of protein complex is prerequisite for aragonite crystallization in the nacreous layer.
abstract: We have isolated a protein complex from the nacreous layer of pearl beads and oyster shells. This complex was mainly composed of pearlin and pearl keratin. Addition of a minute amount of the complex to a calcium-carbonate-saturated solution containing Mg2+ induced aragonite crystallization. The complex was dissociated to individual components in the presence of EDTA and urea. Conversely, the complex was reconstituted from a mixture of components upon incubation with Ca2+ and urea. The mixture of the components was unable to induce aragonite crystallization, but the reconstituted complex recovered this capacity. Thus it is concluded that the complex is the indivisible functional unit required for aragonite crystallization.
authors.affiliation: Department of Molecular Genetics, Kinki University, Wakayama 649-6493, Japan.
authors.forename: Aizo
authors.initials: A
authors.lastname: Matsushiro
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Miyashita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Miyamoto
authors.forename: Kohichi
authors.initials: K
authors.lastname: Morimoto
authors.forename: Ben'ichiro
authors.initials: B
authors.lastname: Tonomura
authors.forename: Akio
authors.initials: A
authors.lastname: Tanaka
authors.forename: Koki
authors.initials: K
authors.lastname: Sato
mesh_terms: D000818:Animals; D002119:Calcium Carbonate / Q000737:chemistry*; D003460:Crystallization; D007633:Keratins / Q000302:isolation & purification; D008274:Magnesium / Q000737:chemistry; D010125:Ostreidae / Q000737:chemistry*; D011487:Protein Conformation; D011506:Proteins / Q000302:isolation & purification*
chemical_list: D011506:Proteins; D007633:Keratins; D002119:Calcium Carbonate; D008274:Magnesium