Novel matrix proteins of Pteria penguin pearl oyster shell nacre homologous to the jacalin-related β-prism fold lectins.
Nacreous layers of pearl oyster are one of the major functional biominerals. By participating in organic compound-crystal interactions, they assemble into consecutive mineral lamellae-like photonic crystals. Their biomineralization mechanisms are controlled by macromolecules; however, they are largely unknown. Here, we report two novel lectins termed PPL2A and PPL2B, which were isolated from the mantle and the secreted fluid of Pteria penguin oyster. PPL2A is a hetero-dimer composed of α and γ subunits, and PPL2B is a homo-dimer of β subunit, all of which surprisingly shared sequence homology with the jacalin-related plant lectin. On the basis of knockdown experiments at the larval stage, the identification of PPLs in the shell matrix, and in vitro CaCO3 crystallization analysis, we conclude that two novel jacalin-related lectins participate in the biomineralization of P. penguin nacre as matrix proteins. Furthermore, it was found that trehalose, which is specific recognizing carbohydrates for PPL2A and is abundant in the secreted fluid of P. penguin mantle, functions as a regulatory factor for biomineralization via PPL2A. These observations highlight the unique functions, diversity and molecular evolution of this lectin family involved in the mollusk shell formation.
The Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan; Center for Interdisciplinary Research, Tohoku University, Sendai 980-8578, Japan.
Takako
T
Naganuma
The Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan.
Wataru
W
Hoshino
The Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan.
Yukihiro
Y
Shikanai
The Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan.
Rie
R
Sato
The Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan.
Kaiyue
K
Liu
The Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan.
Saho
S
Sato
The Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan.
Koji
K
Muramoto
Center for Interdisciplinary Research, Tohoku University, Sendai 980-8578, Japan; Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan.
Makoto
M
Osada
Center for Interdisciplinary Research, Tohoku University, Sendai 980-8578, Japan; Graduate School of Environmental Studies, Tohoku University, Sendai 980-8578, Japan.
Kyosuke
K
Yoshimi
The Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan; Center for Interdisciplinary Research, Tohoku University, Sendai 980-8578, Japan.
Tomohisa
T
Ogawa
D060105:Animal Shells / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D018360:Crystallography, X-Ray; D016326:Extracellular Matrix Proteins / Q000737:chemistry*; D037102:Lectins / Q000737:chemistry*; D049911:Pinctada / Q000737:chemistry* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D040681:Structural Homology, Protein
D016326:Extracellular Matrix Proteins; D037102:Lectins