Murén E, Ek B, Björk I, Rask L
Uppsala Genetic Center, Department of Cell Research, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Eur J Biochem. 1996 Dec 1;242(2):214-9. doi: 10.1111/j.1432-1033.1996.0214r.x.
The 2S storage protein napin from Brassica napus var. L. is synthesised as a precursor protein at the endoplasmic reticulum and transported along a gradient of decreasing pH to the vacuole, where two propeptides are removed to produce mature napin. The structures of pronapin expressed in insect cells and mature napin from rape seed were characterised. Limited proteolysis with several endoproteases cleaved primarily in the propeptides, suggesting that the propeptides are exposed to the exterior of the protein. Immunological comparison in parallel with circular dichroic spectrometry, both at neutral and acid pH, indicated that the propeptides had only a minor influence on the conformation of the regions of the molecule that correspond to mature napin.
来自甘蓝型油菜变种L.的2S贮藏蛋白napin在内质网中以前体蛋白的形式合成，并沿着pH值降低的梯度运输到液泡中，在那里去除两个前肽以产生成熟的napin。对在昆虫细胞中表达的前napin和油菜籽中的成熟napin的结构进行了表征。用几种内切蛋白酶进行的有限蛋白水解主要在原肽中切割，这表明原肽暴露在蛋白质的外部。在中性和酸性pH条件下，通过圆二色光谱法与免疫比较表明，原肽对分子中与成熟napin相对应区域的构象影响较小。
