Sun Zhi, Ahsan Mohammad M, Wang Hongjun, Du Chang, Abbott Christopher, Moradian-Oldak Janet
Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA 90033, USA.
Eur J Oral Sci. 2006 May;114 Suppl 1:59-63; discussion 93-5, 379-80. doi: 10.1111/j.1600-0722.2006.00296.x.
The purpose of this study was to express, characterize, and investigate the self-assembly of a recombinant porcine amelogenin lacking the hydrophilic 24 C-terminal amino acids (rP148). To gain further insight into the function of amelogenin processing during enamel mineralization, this protein was also used as a substrate to examine the action of matrix metalloproteinase-20 (MMP-20). The assembly properties of rP148 were monitored by dynamic light scattering (DLS). In general, rP148 molecules assemble into monomers, dimers, oligomers, and some nanosphere-like particles. Depending on the solution conditions, large aggregates were also observed. Matrix metalloproteinase-20 cleaved the rP148 molecule at a few sites, creating a number of different products, including the tyrosine-rich amelogenin polypeptide (TRAP). Our data suggest that although rP148 self-assembles into small particles, its assembly properties are different from those of the full-length rP172, indicating that the C-terminal 24 amino acids play a critical role in nanosphere assembly. We further demonstrate that MMP-20 digests rP148 in a manner that generates a similar proteolytic pattern, as would be expected to occur in vivo.
本研究的目的是表达、表征并研究一种缺少亲水性24个C末端氨基酸的重组猪釉原蛋白（rP148）的自组装。为了更深入了解釉质矿化过程中釉原蛋白加工的功能，该蛋白还被用作底物来检测基质金属蛋白酶-20（MMP-20）的作用。通过动态光散射（DLS）监测rP148的组装特性。一般来说，rP148分子组装成单体、二聚体、寡聚体以及一些类似纳米球的颗粒。根据溶液条件，还观察到了大的聚集体。基质金属蛋白酶-20在几个位点切割rP148分子，产生许多不同的产物，包括富含酪氨酸的釉原蛋白多肽（TRAP）。我们的数据表明，尽管rP148自组装成小颗粒，但其组装特性与全长rP172不同，这表明C末端的24个氨基酸在纳米球组装中起关键作用。我们进一步证明，MMP-20以一种产生与体内预期相似的蛋白水解模式的方式消化rP148。
