Premium
N‐terminal deletion affects catalytic activity of saporin toxin
Author(s) -
Bonini Francesca,
Traini Roberta,
Comper Fabrizio,
Fracasso Giulio,
Tomazzolli Rossella,
Serra Mauro Dalla,
Colombatti Marco
Publication year - 2006
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.20845
Subject(s) - saporin , ribosome inactivating protein , mutant , cytotoxic t cell , chemistry , cytotoxicity , biochemistry , microbiology and biotechnology , biology , ribosome , gene , in vitro , rna , immunotoxin
Single‐chain ribosome inactivating proteins (RIPs) are cytotoxic components of macromolecular pharmaceutics for immunotherapy of cancer and other human diseases. Saporin belongs to a family of single‐chain RIPs sharing sequence and structure homology. In a preliminary attempt to define an active saporin polypeptide of minimum size we have generated proteins with deletions at the N‐terminus and at the C‐terminus. An N‐terminal (sapΔ1–20) deletion mutant of saporin displayed defective catalytic activity, drastically reduced cytotoxicity but increased ability to interact with liposomes inducing their permeabilization at low pH. A C‐terminal (sapΔ239–253) deletion mutant showed instead a moderate reduction in cytotoxic activity. A substantial alteration of secondary structure was evidenced by Fourier transformed infrared spectroscopy (FTIR) in the sapΔ1–20 mutant. It can be hypothesized that the defective functions of sapΔ1–20 are due to alterations of its spatial configuration. J. Cell. Biochem. 98: 1130–1139, 2006. © 2006 Wiley‐Liss, Inc.