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Kex2‐dependent processing of yeast K 1 killer preprotoxin includes cleavage at ProArg‐44
Author(s) -
Zhu YunSong,
Zhang XiaYing,
Cartwright Charles P.,
Tipper Donald J.
Publication year - 1992
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1992.tb01496.x
Subject(s) - cleavage (geology) , biology , saccharomyces cerevisiae , protease , yeast , n terminus , c terminus , biochemistry , golgi apparatus , microbiology and biotechnology , stereochemistry , peptide sequence , cell , enzyme , chemistry , gene , amino acid , fracture (geology) , paleontology
Summary The K 1 killer toxin of Saccharomyces cerevisiae consists of 103‐ and 83‐residue α and β components whose derivation, from a 316‐residue precursor preprotoxin, requires processing at the α N ‐terminus (after ProArg‐44), the α C ‐terminus (after ArgArg‐149) and at the β N ‐terminus (after LysArg–233). These processing events occur after translocation to the Golgi and have been investigated using β‐lactamase fusions. Signal peptidase cleavage of the precursor, predicted to occur after Ala‐26, was confirmed by N ‐terminal sequence analysis of Ala‐34 and IIe‐52 fusions. Cleavage at all of the other predicted processing sites, including ProArg‐44, is dependent on activity of the Kex2 protease. A fourth Kex2‐dependent cleavage occurs at LysArg‐188. Implications for the specificity of Kex2 cleavage and preprotoxin processing are discussed.