Ilic M Z, Mok M T, Williamson O D, Campbell M A, Hughes C E, Handley C J
Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.
Arch Biochem Biophys. 1995 Sep 10;322(1):22-30. doi: 10.1006/abbi.1995.1431.
The N-terminal amino acid sequence of human aggrecan was determined and it was shown that two sequences were present. The major sequence, AVTVE-, accounted for 60% of the aggrecan and started at alanine residue 17 of the human aggrecan core protein cDNA sequence (K. Doege et al. (1991) J. Biol. Chem. 266, 894-920). The other N-terminal sequence, VETX-, started at valine residue 20. Characterization of aggrecan core protein peptides present in the matrix of adult human articular cartilage showed that at least 11 aggrecan core proteins were present with approximate M(r) between 300,000 and 43,000. All these core proteins were found to have the same N-terminal sequences as that observed in human aggrecan. When articular cartilage was placed in explant culture in medium containing 10(-6) M retinoic acid there was a 3.5-fold increase in the loss of aggrecan into the culture medium compared to tissue maintained in medium alone or medium containing 20% (v/v) newborn calf serum. Analysis of the aggrecan core protein fragments that were released to the culture medium containing 10(-6) M retinoic acid showed the presence of 13 core protein peptides of M(r) between 300,000 and 43,000. The 11 smaller peptides of M(r) 230,000 to 43,000 were shown to have the N-terminal sequence ARGS-. This sequence which starts at residue 393 of the human aggrecan core protein is located within the interglobular region between the G1 and G2 domains and is the site of aggrecan catabolism by the putative protease aggrecanase. The presence of core proteins of varying sizes but with the same N-terminal sequence reflects proteolytic processing from the C-terminal end of the core protein that was also observed in the aggrecan macromolecules extracted from the matrix of human articular cartilage. This proteolytic processing was also evident but to a lesser extent in newly synthesized 35S-labeled aggrecan macromolecules.
已确定人聚集蛋白聚糖的N端氨基酸序列，结果显示存在两种序列。主要序列AVTVE -，占聚集蛋白聚糖的60%，起始于人聚集蛋白聚糖核心蛋白cDNA序列的丙氨酸残基17（K. Doege等人，(1991) J. Biol. Chem. 266, 894 - 920）。另一个N端序列VETX -，起始于缬氨酸残基20。对成人关节软骨基质中存在的聚集蛋白聚糖核心蛋白肽段的表征表明，至少存在11种聚集蛋白聚糖核心蛋白，其近似相对分子质量在300,000至43,000之间。所有这些核心蛋白的N端序列都与人聚集蛋白聚糖中观察到的相同。当将关节软骨置于含有10(-6) M视黄酸的培养基中进行外植体培养时，与单独培养基或含有20%（v/v）新生牛血清的培养基中培养的组织相比，聚集蛋白聚糖向培养基中的损失增加了3.5倍。对释放到含有10(-6) M视黄酸的培养基中的聚集蛋白聚糖核心蛋白片段的分析表明，存在13种相对分子质量在300,000至43,000之间的核心蛋白肽段。相对分子质量为230,000至43,000的11个较小肽段显示具有N端序列ARGS -。该序列起始于人聚集蛋白聚糖核心蛋白的残基393，位于G1和G2结构域之间的球间区域内，是假定的蛋白酶聚集蛋白聚糖酶对聚集蛋白聚糖进行分解代谢的位点。不同大小但具有相同N端序列的核心蛋白的存在反映了从核心蛋白C端进行的蛋白水解加工，这在从人关节软骨基质中提取的聚集蛋白聚糖大分子中也观察到。这种蛋白水解加工在新合成的35S标记的聚集蛋白聚糖大分子中也很明显，但程度较轻。
