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Characterization and Polyelectrolyte Precipitation of β‐Galactosidase Containing Genetic Fusions of Charged Polypeptides
Author(s) -
Niederauer Mark Q.,
Suominen Ilari,
Rougvie Malcolm A.,
Ford Clark F.,
Glatz Charles E.
Publication year - 1994
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp00027a001
Subject(s) - polyelectrolyte , chemistry , precipitation , lysine , enzyme , nucleic acid , chromatography , biochemistry , biophysics , amino acid , biology , polymer , organic chemistry , physics , meteorology
Genetically engineered versions of β‐galactosidase were constructed through the addition of charged polypeptide fusion tails for the purpose of enhancing polyelectrolyte precipitation. Negatively charged aspartic acid tails and positively charged poly(arginine) tails were added to β‐galactosidase from Escherichia coli. These fusion proteins were all shown to possess specific activity equal to that of the native enzyme. Gel permeation and ion‐exchange chromatography provided evidence concerning the integrity of the tails as well as their altered charge characteristics. All enzymes containing charged tails displayed enhanced polyelectrolyte precipitation over the native enzyme. An optimal number of charged residues, beyond which no further enhancement of precipitation was observed, was found to be approximately 10 residues for each type of tail. No interference from nucleic acids was observed in the precipitation of positively tailed β‐galactosidase.