원문정보
초록
영어
In diatom Cylindrotheca fusiformis, modified peptides called silaffin polypeptides are responsible for silica deposition in vivo at ambient condition1. Recently, it was discovered that the synthetic R5 peptide, the repeat unit of silaffin polypeptide without posttranslational modification, was capable of precipitating silica in vitro at ambient condition2. Herein, chemiric proteins were generated by incorporating synthetic silaffin domains (R1-R7) from Cylindrotheca fusiformis onto green fluorescent protein (GFP) by genetic engineering3. His tagged chimeric proteins were accommodated using selfassembled monolayer of disulfide-NTA after chelating with Ni2+ ions on Au surface. Biosilicification catalyzed by silafifn chimeric protein was monitored in situ using quartz crystal microbalance (QCM) after injection of prehydrolyzed TMOS. It was found out that
the kinetics of silaffin polypeptide catalyzed biosilicfication is the first order. And the biosilicification is composed of two different stages. At initial stage, the process of biosilicificaiton is dominant by catalysis of silaffin polypeptide and terminates in only 2
minutes. And then, spontaneous silica polymerization occurs in the second step. Silica
nanoparticles deposited on Au gold were analyzed using SEM, STEM, AFM, and confocal
microscope. The morphology of silica nanoparticles is heterogeneous with the size
distribution ranging from 10 nm to 100 nm. This is the first demonstration for biosilicification kinetics catalyzed by silaffin polypeptide.