| Autor: |
Rivera-Perez C; CONACYT-Centro de Investigaciones Biológicas del Noroeste (CIBNOR), Avenida Instituto Politécnico Nacional No. 195, Playa Palo de Sta. Rita Sur, Apartado Postal 128, 23096, La Paz, Baja California Sur, Mexico., Flores-Sánchez IA; Tecnológico Nacional de México, La Paz, Baja California Sur, Mexico., Ojeda Ramírez de Areyano JJ; Centro de Investigaciones Biológicas del Noroeste (CIBNOR), Avenida Instituto Politécnico Nacional No. 195, Playa Palo de Sta. Rita Sur, Apartado Postal 128, 23096, La Paz, Baja California Sur, Mexico., Rojas Posadas DI; Centro de Investigaciones Biológicas del Noroeste (CIBNOR), Avenida Instituto Politécnico Nacional No. 195, Playa Palo de Sta. Rita Sur, Apartado Postal 128, 23096, La Paz, Baja California Sur, Mexico., Hernández-Saavedra NY; Centro de Investigaciones Biológicas del Noroeste (CIBNOR), Avenida Instituto Politécnico Nacional No. 195, Playa Palo de Sta. Rita Sur, Apartado Postal 128, 23096, La Paz, Baja California Sur, Mexico. nhernan04@cibnor.mx. |
| Abstrakt: |
Nacre is the main component of the pearl oyster shells and it is synthesized by specialized soluble and insoluble shell matrix proteins. Insoluble proteins from the decalcification of the shell are the less studied proteins due to the technical problems to isolate them from the organic matrix. In this study, an insoluble shell matrix protein from Pinctada mazatlanica, pearlin (Pmaz-pearlin), was successfully cloned from the mantle tissue, and the native protein isolated from the shell was functionally characterized. The full coding sequence of Pmaz-pearlin mRNA consists of 423 base pairs, which encode to a 16.3 kDa pearlin. Analysis of the deduced amino acid sequence revealed that Pmaz-pearlin contained four acidic regions, an NG repeat domain, and Cys conserved residues, the latter potentially forms four disulfide bridges which might stabilize the protein structure. The isolated protein from the shell is a glycoprotein of ~ 16.74 kDa which can produce aragonite and calcite crystals in vitro. Our results show that Pmaz-pearlin is a well-conserved protein involved in nacre layer growth, which produces calcite crystals in the presence of CaCl 2 , aragonite crystal polymorphs with a hexagonal structure in the presence of MgCl 2 , and needle-like crystal structure polymorphs in the presence of CaCO 3 The identity of the crystals was confirmed using RAMAN analyses. |
