Human matrix metalloproteinase proMMP-9 is secreted as latent zymogen, which requires two-steps proteolytic activation. The secreted proMMP-9 is glycosylated at two positions: Asn38 and Asn120 located in the prodomain and catalytic domain, respectively. It has been demonstrated that glycosylation at Asn120 is required for secretion of the enzyme, while the role of Asn38 glycosylation is not well understood, but is usually linked to the activation process. One hypothesis stated that the Asn38 glycosylation might protect against proteolytic activation. However, the activation process occurs with or without the presence of this glycosylation. We conducted molecular dynamics (MD) simulations on the glycosylated and non-glycosylated proMMP-9 to elucidate the effect of Asn38 glycosylation on this two-step activation process. The simulation results suggest that Asn38 glycosylation does not hinder the activation process directly, but induces conformational changes in the vicinity of the first proteolytic region in such a way that E⁵⁹-M⁶⁰ cleavage is processed before R¹⁰⁶-F¹⁰⁷. These results correlate with analysis provided by Boon et al. and experimental data from Ogata et al. who attempted to determine the order of events in activation of proMMP-9. Results from additional MD simulations for the model of glycosylated proMMP-9 bound to galectin-8 N-domain suggest that Gal-8 by interacting with Asn38 glycan might further facilitate processing of the first cleavage between E⁵⁹-M⁶⁰. Thus, our simulation results suggest that both Asn38 glycosylation and interaction with Gal-8N may be involved in facilitating and the temporal order of the activation process of pro-MMP9. The aim of this report is to provide an inspiration for future detailed experiments aimed at explaining the role of N-glycosylation in the activation process of prodomain of MMP-9.

人基质金属蛋白酶proMMP-9被分泌为潜在的酶原，需要两步蛋白水解激活。分泌的proMMP-9在两个位置被糖基化：分别位于前结构域和催化结构域的Asn38和Asn120。已经证明，Asn120的糖基化是酶的分泌所必需的，而Asn38糖基化的作用尚不清楚，但通常与激活过程有关。一种假设表明，Asn38糖基化可能会防止蛋白水解激活。但是，激活过程会在有或没有这种糖基化的情况下发生。我们对糖基化和非糖基化的proMMP-9进行了分子动力学（MD）模拟，以阐明Asn38糖基化对这一两步激活过程的影响。在R ¹⁰⁶ -F ¹⁰⁷之前处理⁵⁹ -M ⁶⁰裂解。这些结果与Boon等人提供的分析相关。和绪方等人的实验数据。谁试图确定激活proMMP-9的事件顺序。结合半乳糖凝集素8 N结构域的糖基化proMMP-9模型的其他MD模拟结果表明，Gal-8通过与Asn38聚糖相互作用可能进一步促进E ⁵⁹ -M ⁶⁰之间的第一次切割。因此，我们的模拟结果表明，Asn38糖基化和与Gal-8N的相互作用都可能参与促进MMP9激活过程的时间顺序。本报告的目的是为未来的详细实验提供灵感，这些实验旨在解释N-糖基化在MMP-9前域激活过程中的作用。