Title: Misfolding of chloramphenicol acetyltransferase due to carboxy-terminal truncation can be corrected by second-site mutations
Authors: Van der Schueren, J ×
Robben, Johan
Volckaert, Guido #
Issue Date: Dec-1998
Publisher: Oxford univ press
Series Title: Protein engineering vol:11 issue:12 pages:1211-1217
Abstract: Folding of chloramphenicol acetyltransferase (CAT) in Escherichia coli is hampered by deletion of the carboxy-terminal tail including the last residue of the carboxy-terminal alpha-helix. Such truncated CAT polypeptides quantitatively aggregate into cytoplasmic inclusion bodies, which results in absence of a chloramphenicol-resistant phenotype for the producing host. In this paper, a genetic approach is presented to examine this aggregation process in more detail. Random mutagenesis of inactive CAT followed by direct phenotypic selection for revertants with restored chloramphenicol resistance was used to isolate second-site suppressors of inactive truncation mutants of CAT. Tno random mutagenesis procedures, independently of each other, yielded a unique substitution of Phe for Leu at amino acid position 145. This second-site mutation does not drastically affect the proteins' stability under normal growth conditions of E. coli, Hence, the introduction of Phe at amino acid position 145 improves the ability of the protein to fold into a soluble, enzymatically active conformation. The conservative character of the Leu145Phe replacement indicates that limited changes at crucial positions can have important effects on protein folding ira vivo.
ISSN: 0269-2139
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Division of Gene Technology (-)
Biochemistry, Molecular and Structural Biology Section
× corresponding author
# (joint) last author

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