Neame P J, Young C N, Treep J T
Department of Biochemistry and Molecular Biology, University of South Florida, College of Medicine, Tampa 33612.
J Biol Chem. 1990 Nov 25;265(33):20401-8.
A protein rich in proline and arginine (proline/arginine-rich protein (PARP] has been isolated from dissociative extracts of bovine nasal and articular cartilage, and its primary structure has been determined. The protein has 218 amino acids, giving a calculated protein Mr of 24,075. In nasal cartilage, this protein is in molar concentrations equivalent to 1/20-1/10 that of the link protein of cartilage proteoglycan aggregates. PARP has also been isolated from bovine articular cartilage, bovine fetal epiphysis, and nonossified human tarsal bones. PARP is similar to various collagen NH2-terminal domains. It is 49% identical to the NH2-terminal end of collagen alpha 1 (XI), 17% identical to the NC4 domain of collagen alpha 1 (IX), and 14% identical to the NC3 domain of collagen alpha 1 (XII). Four cysteines are conserved between type XI collagen and PARP, and these form two disulfide bonds. Two of the cysteines are also conserved between PARP and collagens IX and XII. The homology between the collagens and PARP makes it possible to speculate on the likely disulfide bond pattern in the collagen NH2-terminal domains. It is probable that PARP is a collagen fragment removed during processing in a manner analogous to chondrocalcin (the C-terminal propeptide of type II collagen).
一种富含脯氨酸和精氨酸的蛋白质（富含脯氨酸/精氨酸的蛋白质，PARP）已从牛鼻软骨和关节软骨的解离提取物中分离出来，其一级结构已被确定。该蛋白质有218个氨基酸，计算出的蛋白质分子量为24,075。在鼻软骨中，这种蛋白质的摩尔浓度相当于软骨蛋白聚糖聚集体连接蛋白的1/20 - 1/10。PARP也已从牛关节软骨、牛胎儿骨骺和未骨化的人类跗骨中分离出来。PARP与各种胶原蛋白的NH2末端结构域相似。它与胶原蛋白α1(XI)的NH2末端有49%的同一性，与胶原蛋白α1(IX)的NC4结构域有17%的同一性，与胶原蛋白α1(XII)的NC3结构域有14%的同一性。XI型胶原蛋白和PARP之间有四个半胱氨酸是保守的，它们形成两个二硫键。其中两个半胱氨酸在PARP与IX型和XII型胶原蛋白之间也是保守的。胶原蛋白和PARP之间的同源性使得推测胶原蛋白NH2末端结构域中可能的二硫键模式成为可能。PARP很可能是在加工过程中以类似于软骨钙素（II型胶原蛋白的C末端前肽）的方式被去除的胶原蛋白片段。
