MATURATION OF EXPORTED PROTEINS IN ESCHERICHIA-COLI - REQUIREMENT FOR ENERGY, SITE AND KINETICS OF PROCESSING

  • 1 January 1982
    • journal article
    • research article
    • Vol. 124  (3) , 561-566
Abstract
Precursor forms of periplasmic and outer membrane proteins were accumulated in phenethylalcohol-treated [E. coli] cells in membrane fractions. After removal of phenethyl alcohol, maturation occurred in the absence but not in the presence of carbonylcyanide m-chlorophenylhydrazone (30 .mu.M). The site and kinetics of processing were investigated for OmpA, LamB and OmpF proteins and for maltose binding protein and TEM .beta.-lactamase. With regard to sites of processing, no fundamental difference between outer membrane and periplasmic proteins was observed. For maltose binding protein and TEM .beta.-lactamase, maturation, like that of outer membrane protein precursors, occurred in membrane fractions. Processing of pro-OmpA protein was about as fast as that of pro-LamB protein, whereas pro-OmpF protein appeared to mature more slowly. While carbonylcyanide m-chlorophenylhydrazone (30 .mu.M) prevented processing of all precursor forms, arsenate, which altered formation of ATP even when it was used at 1 mM, did not totally prevent maturation occurring. These results are discussed with regard to the biosynthesis and assembly of exported proteins.

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