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Isolation and characterization of new C‐terminal substitution mutations affecting secretion of polygalacturonase in Erwinia carotovora ssp. carotovora
Author(s) -
Palomäki T,
Saarilahti H.T
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(96)01369-5
Subject(s) - erwinia , secretion , pectinase , biochemistry , chemistry , mutant , residue (chemistry) , enzyme , gene
An intact C‐terminus was previously shown to be required for stability and secretion of the polygalacturonase (PehA) in Erwinia carotovora ssp. carotovora . Here we have analyzed the effects of amino acid (aa) substitutions generated to five C‐terminal positions of PehA. Conservation of two hydrophobic and one non‐hydrophobic residue (V372, V374 and N371, respectively) was found to be essential for maintenance of the protein stability. As an exception, one of the mutants (V372G) did not show major effects on protein stability, as determined by immunoblots and enzyme activity assay, yet it prevented the secretion completely. We conclude that the C‐terminus of PehA is directly involved in the formation or stabilization of a conformation‐sensitive structure needed for recognition of the protein as secreted.