Yeast KEX2 recognition sequences

John Manfredi 71053.3661 at COMPUSERVE.COM
Sun Mar 9 13:00:36 EST 1997


Tan Nguan Soon writes:

Does anyone know the recognition peptide sequences for S. cereveise KEX2
endopeptidase? I know that it cleave at Lys-Arg site, but certainly a longer
sequence is necessary for recognition. Please help. Any references?

________________________________________________

Howdy Tan,

See  Brenner, C., and Fuller, R.S. 1992.  Structural and enzymatic
characterization of a purified prohormone-processing enzyme: secreted, soluble
Kex2 protease.  Proc. Natl. Acad. Sci. USA 89:922-926.  Briefly, this study
shows that The KEX2 protein is sensitive to the composition of the two residues
preceding the cleavage site. If, instead of the normal KR, either RR or KK is
present, the affinity of KEX2 for the substrate is reduced; replacement of the
normal K at position P2 with P, A, T, or G also dramatically reduced the
affinity of KEX2 for the substrate.  But the activity of KEX2 was also sensitive
to residues at the P4 position, exhibiting a preference for aliphatic residues.
In contrast, substitutions at the P3 position of the substrate have little
effect on KEX2 activity: substrates with aromatic (Y), aliphatic (L), and
strongly hydrophilic (Q) residues at P3 are cleaved with similar kinetics.  

.Also check out references in: Sprague, G.F., Jr., and J.W. Thorner. 1992.
Pheromone response and signal transduction during the mating process of
Saccharomyces cerevisiae, pp 657-744. In E.W.Jones, J.R.Pringle, and J.R.Broach
(ed.), The Molecular and Cellular Biology of the Yeast Saccharomyces: Gene
Expression. Cold Spring Harbor Laboratory Press, New York.

John Manfredi
Cadus Pharmaceutical




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