Folding <i>in vitro</i> and transport <i>in vivo</i> of pre‐β‐lactamase are SecB independent

Abstract

Summary The rate of folding of the precursor of β‐lactamase is not influenced by the presence of SecB under conditions in which GroEL/ES retards the folding. Wild‐type β‐lactamase and several mutants in the signal or the mature protein, affecting either transport or enzyme kinetics and probably folding, were examined for total expression, total enzymatic activity, and transported β‐lactamase ( in vivo resistance) in secB ‐ and secB + strains. We conclude that there is no indication of any relevant interaction between SecB and pre‐β‐lactamase in vitro , nor did the secB ‐ mutation affect the transport of wild–type β‐lactamase or any of the mutants in vivo. Thus, putative Escherichia coli ‘folding modulators’must be of limited specificity.