Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10767362 | Biochemical and Biophysical Research Communications | 2007 | 6 Pages |
Abstract
Shiga toxin has a protease-sensitive site in the disulfide loop region of the A-chain. Cleavage of this site by furin is essential for rapid intoxication of cells by Shiga toxin. We have here investigated whether in addition to the Arg-X-X-Arg sequence, there are other structural requirements in the disulfide loop region for furin cleavage. A toxin mutant (Shiga-2D toxin) still containing the consensus motif for cleavage by furin, but lacking ten amino acids in the disulfide loop, was generated. Trypsin was able to cleave Shiga-2D toxin in vitro, demonstrating that the protease-sensitive region is intact. However, Shiga-2D toxin was not efficiently cleaved by furin either in vitro or in vivo. Furthermore, unless it was precleaved with trypsin, Shiga-2D toxin was much less toxic than wild type Shiga toxin in LoVo cells expressing functional furin. In contrast, LoVo/neo cells lacking functional furin were unable to activate both wild type Shiga toxin and Shiga-2D toxin. In conclusion, an extended loop structure is required for furin-induced cleavage of Shiga toxin.
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Authors
Alma Kurmanova, Alicia Llorente, Anna Polesskaya, Ãystein Garred, Sjur Olsnes, Juri Kozlov, Kirsten Sandvig,