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Characterization of an Escherichia coli rotA mutant, affected in periplasmic peptidyl‐prolyl cis/trans isomerase
Author(s) -
Kleerebezem Michiel,
Heutink Marja,
Tommassen Jan
Publication year - 1995
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.1365-2958.1995.mmi_18020313.x
Subject(s) - periplasmic space , biology , mutant , bacterial outer membrane , escherichia coli , protein folding , peptidylprolyl isomerase , biochemistry , isomerase , gene , microbiology and biotechnology
The rotA gene of Escherichia coli encodes a peptidyl‐prolyl cis/trans isomerase (PPlase), which is supposed to catalyse protein folding in the periplasm. To investigate the importance of the enzyme, the rotA gene was cloned and a chromosomal deletion mutant was created. The rotA mutant was normally viable. No residual PPlase activity could be detected in the periplasmic fraction of the mutant. Comparison of the patterns of periplasmic and outer membrane proteins by SDS‐PAGE revealed no differences in protein composition between the rotA mutant and its parental strain. Similarly, the kinetics of periplasmic protein folding and outer membrane protein assembly appeared unaffected by the rotA mutation. Our results show that the periplasmic PPlase of E. coli is not essential and that the protein does not play an important role in protein folding.