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Title:
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Insertion of a malE B-Galactosidase fusion protein into the envelope of Escherichia coli disrupts biogenesis of outer membrane proteins and processing of inner membrane proteins
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Author:
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Herrero Perpiñán, Enrique; Jackson, Maria; Bassford, Phillip J.; Sinden, David; Holland, I. Barry
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Notes:
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The synthesis of a membrane-bound MalE ,B-galactosidase hybrid protein,
when induced by growth of Escherichia coli on maltose, leads to inhibition of cell
division and eventually a reduced rate of mass increase. In addition, the relative
rate of synthesis of outer membrane proteins, but not that of inner membrane
proteins, was reduced by about 50%o. Kinetic experiments demonstrated that this
reduction coincided with the period of maximum synthesis of the hybrid protein
(and another maltose-inducible protein, LamB). The accumulation of this abnormal
protein in the envelope therefore appeared specifically to inhibit the synthesis,
the assembly of outer membrane proteins, or both, indicating that the hybrid
protein blocks some export site or causes the sequestration of some limiting
factor(s) involved in the export process. Since the MalE protein is normally
located in the periplasm, the results also suggest that the synthesis of periplasmic
and outer membrane proteins may involve some steps in common. The reduced
rate of synthesis of outer membrane proteins was also accompanied by the
accumulation in the envelope of at least one outer membrane protein and at least
two inner membrane proteins as higher-molecular-weight forms, indicating that
processing (removal of the N-terminal signal sequence) was also disrupted by the
presence of the hybrid protein. These results may indicate that the assembly of
these membrane proteins is blocked at a relatively late step rather than at the level
of primary recognition of some site by the signal sequence. In addition, the results
suggest that some step common to the biogenesis of quite different kinds of
envelope protein is blocked by the presence of the hybrid protein. |
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Subject(s):
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-Escheríchia coli
-Proteïnes
-Escheríchia coli |
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Rights:
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(c) American Society for Microbiology, 1982
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Document type:
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article
publishedVersion |
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Published by:
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American Society for Microbiology
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Share:
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