The link proteins.
The link proteins.
复制标题
连接蛋白。
DOI：
10.1007/978-3-0348-7545-5_5
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Barry,FP
中科院分区：
文献类型：
--
作者：
Neame,PJ;Barry,FP
软骨素-硫酸角蛋白聚糖（聚集蛋白）和透明质酸（透明质酸）的聚集体是软骨的主要空间填充成分。糖蛋白，连接蛋白（LP; 40-48 kDa）通过结合透明质酸和聚集蛋白来稳定聚集体。在没有LP的情况下，与LP存在时相比，聚集体更小（通过电子显微照片的旋转阴影估计）且更不稳定（它们在pH 5时解离）。蛋白多糖聚集体，包括LP，在混乱物如4 M胍盐酸盐存在下解离。去除混沌后，复合体将重新结合。这形成了LP与软骨分离的基础，并已在其他地方详细描述。蛋白聚糖聚集体的胰蛋白酶消化产生高分子量的产物，该产物由透明质酸结合LP和聚集蛋白的n端球形结构域（透明质酸结合区；HABR）组成，其化学计量为1:1。LP和HABR的氨基酸序列惊人地相似。氨基酸序列可分为三个结构域；一个属于免疫球蛋白超家族的n端结构域和两个彼此相似的c端结构域。DNA结构与这种相似性相呼应，因为LP和HABR的主要结构域都反映在三个独立的外显子上。这两个c端结构域主要负责与HA的关联，并且与最近描述的两种透明质酸结合蛋白CD44和TSG-6有关。各种各样的方法，包括LP在体内的形式分析，旋转阴影和免疫球蛋白样结构域序列分析，已经为LP的结构-功能关系提供了大量的线索。本文详细介绍了LP的结构和功能，重点介绍了LP与HABR及其相关分子如免疫球蛋白和淋巴细胞ha受体的相似性。
Aggregates of chondroitin-keratan sulfate proteoglycan (aggrecan) and hyaluronic acid (hyaluronan) are the major space-filling components of cartilage. A glycoprotein, link protein (LP; 40-48 kDa) stabilizes the aggregate by binding to both hyaluronic acid and aggrecan. In the absence of LP, aggregates are smaller (as estimated by rotary shadowing of electron micrographs) and less stable (they dissociate at pH 5) than they are in the presence of LP. The proteoglycan aggregate, including LP, is dissociated in the presence of chaotropes such as 4 M guanidine hydrochloride. On removal of the chaotrope, the complex will reassociate. This forms the basis of the isolation of LP from cartilage and has been described in detail elsewhere. Tryptic digestion of the proteoglycan aggregates results in a high molecular weight product that consists of hyaluronic acid to which is bound LP and the N-terminal globular domain of aggrecan (hyaluronic acid binding region; HABR) in a 1: 1 stoichiometry. The amino acid sequences of LP and HABR are surprisingly similar. The amino acid sequence can be divided into three domains; an N-terminal domain that falls into the immunoglobulin super-family and two C-terminal domains that are similar to each other. The DNA structure echoes this similarity, in that the major domains are reflected in three separate exons in both LP and HABR. The two C-terminal domains are largely responsible for the association with HA and are related to two recently described hyaluronate-binding proteins, CD44 and TSG-6. A variety of approaches, including analysis of the forms of LP in vivo, rotary shadowing and analysis of the sequence in the immunoglobulin-like domain, have shed considerable light on the structure-function relationships of LP. This review describes the structure and function of LP in detail, focusing on what can be inferred from the similarity of LP, HABR and related molecules such as immunoglobulins and lymphocyte HA-receptors.