Averyhart-Fullard V, Datta K, Marcus A
Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111.
Proc Natl Acad Sci U S A. 1988 Feb;85(4):1082-5. doi: 10.1073/pnas.85.4.1082.
A cDNA clone that hybridizes to an mRNA (1A10) that accumulates to a substantial level in the axis of the germinating soybean seed was sequenced. The amino acid sequence of the clone indicates an almost perfect repeat of Pro-Pro-Val-Tyr-Lys resulting in a protein containing 40% proline and lacking serine and histidine. On the likelihood that such a protein might be a hydroxyproline-rich cell-wall glycoprotein (HRGP), cell walls of a soybean cell culture were extracted by procedures used to obtain soluble basic cell-wall glycoproteins, and the proteins were fractionated and purified. A 33-kDa protein (and possibly a 28-kDa protein) was obtained that has an amino acid distribution similar to that of the cDNA clone. The protein lacks histidine and serine and contains 20% hydroxyproline and 20% proline. The HRGP is thus distinct both in its amino acid content and in its pentameric repeat of Pro-Pro-Val-Tyr-Lys, with half of the prolines being hydroxylated.
对一个与在萌发大豆种子胚轴中大量积累的mRNA（1A10）杂交的cDNA克隆进行了测序。该克隆的氨基酸序列显示出Pro-Pro-Val-Tyr-Lys几乎完美的重复，形成了一种含40%脯氨酸且缺乏丝氨酸和组氨酸的蛋白质。鉴于这样一种蛋白质可能是富含羟脯氨酸的细胞壁糖蛋白（HRGP），采用用于获得可溶性碱性细胞壁糖蛋白的方法提取了大豆细胞培养物的细胞壁，并对蛋白质进行了分级分离和纯化。得到了一种33 kDa的蛋白质（可能还有一种28 kDa的蛋白质），其氨基酸分布与cDNA克隆相似。该蛋白质缺乏组氨酸和丝氨酸，含有20%的羟脯氨酸和20%的脯氨酸。因此，HRGP在氨基酸组成及其Pro-Pro-Val-Tyr-Lys五聚体重复序列方面都很独特，其中一半的脯氨酸被羟基化。
