Department of Microbiology and Biochemistry, University of the Free State, 205 Nelson Mandela Drive, Park West, Bloemfontein 9301, South Africa.
Cells. 2022 Jan 27;11(3):437. doi: 10.3390/cells11030437.
In this contribution, we report on the possibility that cryptococcal protease(s) could activate the SARS-CoV-2 spike (S) protein. The S protein is documented to have a unique four-amino-acid sequence (underlined, SPRRAR↓S) at the interface between the S1 and S2 sites, that serves as a cleavage site for the human protease, furin. We compared the biochemical efficiency of cryptococcal protease(s) and furin to mediate the proteolytic cleavage of the S1/S2 site in a fluorogenic peptide. We show that cryptococcal protease(s) processes this site in a manner comparable to the efficiency of furin ( > 0.581). We conclude the paper by discussing the impact of these findings in the context of a SARS-CoV-2 disease manifesting while there is an underlying cryptococcal infection.
在本研究中，我们提出隐球菌蛋白酶可能会激活新冠病毒刺突（S）蛋白这一假设。有文献报道，新冠病毒 S 蛋白的 S1 和 S2 结构域连接处存在独特的四氨基酸序列（下划线，SPRRA↓S），是人类蛋白酶弗林（furin）的酶切位点。我们比较了隐球菌蛋白酶和弗林酶对荧光肽 S1/S2 位点的酶切效率。实验结果显示，隐球菌蛋白酶对该位点的酶切效率与弗林酶相当（>0.581）。最后，我们讨论了在新冠病毒感染的同时存在隐球菌感染的情况下，这些发现的意义。
