Vacuolar processing enzyme is self‐catalytically activated by sequential removal of the C‐terminal and N‐terminal propeptides

FEBS Letters

Nishimura, Mikio¹  Hiraiwa, Nagako¹  Hara-Nishimura, Ikuko¹ 

[1] Department of Cell Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan

关键词: Asparaginyl endopeptidase;    Castor bean;    Legumain homologue;    Proprotein processing;    Vacuolar processing enzyme;    Vacuole;   

DOI  :  10.1016/S0014-5793(99)00286-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A vacuolar processing enzyme (VPE) responsible for maturation of various vacuolar proteins is synthesized as an inactive precursor. To clarify how to convert the VPE precursor into the active enzyme, we expressed point mutated VPE precursors of castor bean in the pep4 strain of Saccharomyces cerevisiae. A VPE with a substitution of the active site Cys with Gly showed no ability to convert itself into the mature form, although a wild VPE had the ability. The mutated VPE was converted by the action of the VPE that had been purified from castor bean. Substitution of the conserved Asp-Asp at the putative cleavage site of the C-terminal propeptide with Gly-Gly abolished both the conversion into the mature form and the activation of the mutated VPE. In vitro assay with synthetic peptides demonstrated that a VPE exhibited activity towards Asp residues and that a VPE cleaved an Asp-Gln bond to remove the N-terminal propeptide. Taken together, the results indicate that the VPE is self-catalytically maturated to be converted into the active enzyme by removal of the C-terminal propeptide and subsequent removal of the N-terminal one.

【 授权许可】

Unknown