Interaction of pro-matrix metalloproteinase-9/proteoglycan heteromer with gelatin and collagen
Interaction of pro-matrix metalloproteinase-9/proteoglycan heteromer with gelatin and collagen
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DOI：
10.1074/jbc.m709140200
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发表时间：
2008-05-16
影响因子：
4.8
通讯作者：
Winberg, Jan-Olof
中科院分区：
文献类型：
--
作者：
Malla, Nabin;Berg, Eli;Winberg, Jan-Olof
以前，我们已经表明，THP-1细胞合成基质金属蛋白酶-9（MMP-9），其中一部分酶与蛋白聚糖（PG）核心蛋白紧密相连。在目前的工作中，我们表明，这些pro-MMP-9中心点PG异聚体具有不同的生化特性相比，单体形式的pro-MMP-9。在这些异聚体中，酶的催化位点中的纤连蛋白II样结构域被隐藏，并且纤连蛋白II样介导的与明胶和胶原的结合被阻止。然而，一部分的pro-MMP-9中心点PG异聚体与明胶和胶原相互作用。这种相互作用不是通过PG分子的硫酸软骨素（CS）部分，而是通过PG核心蛋白中的一个区域，一个由MMP-9原和PG核心蛋白相互作用诱导的新位点，或PG分子的非CS糖胺聚糖部分。pro-MMP-9中心点PG异聚体与明胶之间的相互作用弱于pro-MMP-9与明胶之间的相互作用。相比之下，胶原蛋白I以大致相同的亲和力结合到pro-MMP-9中心点PG异聚体和pro-MMP-9。从异聚体的PG部分去除CS链不影响与明胶和胶原的结合。尽管PG核心蛋白的身份未知，但这对异聚体或其前MMP-9组分的所述生物化学性质没有任何影响。还表明，不是pro-MMP-9中心点PG异聚体的一部分的一小部分PG可以结合明胶。至于pro-MMP-9中心点PG异聚体，这与CS链无关。介导游离PG与明胶结合的结构与pro-MMP-9中心点PG异聚体中的相应结构不同，因为它们在完全不同的条件下从明胶-琼脂糖柱洗脱。尽管仅形成少量的pro-MMP-9中心点PG异聚体，但异聚体可能具有基本的生理重要性，因为仅需要催化量的酶来消化生理靶标。
Previously we have shown that THP-1 cells synthesize matrix metalloproteinase-9 (MMP-9) where a fraction of the enzyme is strongly linked to a proteoglycan ( PG) core protein. In the present work we show that these pro-MMP-9 center dot PG heteromers have different biochemical properties compared with the monomeric form of pro-MMP-9. In these heteromers, the fibronectin II-like domain in the catalytic site of the enzyme is hidden, and the fibronectin II-like-mediated binding to gelatin and collagen is prevented. However, a fraction of the pro-MMP-9 center dot PG heteromers interacted with gelatin and collagen. This interaction was not through the chondroitin sulfate (CS) part of the PG molecule but, rather, through a region in the PG core protein, a new site induced by the interaction of pro-MMP-9 and the PG core protein, or a non-CS glycosaminoglycan part of the PG molecule. The interaction between pro-MMP-9 center dot PG heteromers and gelatin was weaker than the interaction between pro-MMP-9 and gelatin. In contrast, collagen I bound to pro-MMP-9 center dot PG heteromers and pro-MMP-9 with approximately the same affinity. Removal of CS chains from the PG part of the heteromers did not affect the binding to gelatin and collagen. Although the identity of the PG core protein is not known, this does not have any impact on the described biochemical properties of the heteromer or its pro-MMP-9 component. It is also shown that a small fraction of the PG, which is not a part of the pro-MMP-9 center dot PG heteromer, can bind gelatin. As for the pro-MMP-9 center dot PG heteromers, this was independent of the CS chains. The structure that mediates the binding of free PG to gelatin is different from the corresponding structure in the pro-MMP-9 center dot PG heteromer, because they were eluted from gelatin-Sepharose columns under totally different conditions. Although only a small amount of pro-MMP-9 center dot PG heteromer is formed, the heteromer may have fundamental physiological importance, because only catalytic amounts of the enzyme are required to digest physiological targets.