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The Aeromonas hydrophila exeE gene, required both for protein secretion and normal outer membrane biogenesis, is a member of a general secretion pathway
Author(s) -
Jiang Bo,
Howard S. Peter
Publication year - 1992
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.1365-2958.1992.tb00856.x
Subject(s) - biology , operon , secretion , bacterial outer membrane , mutant , biogenesis , aeromonas hydrophila , gene , extracellular , membrane protein , microbiology and biotechnology , genetics , biochemistry , bacteria , escherichia coli , membrane
Summary The Aeromonas hydrophila Tn 5–751 insertion mutant L1.97 is unable to secrete extracellular proteins, and is fragile because of defective assembly of its outer membrane. A Kpnl 4.1 kb fragment, which complements this mutant when supplied with an exogenous promoter, was isolated and sequenced. It contains two complete genes, exeE and exeF, plus fragments of two others and may form part of an operon. The exeE and exef open reading frames encode 501‐residue M, 55882 and 388‐residue M, 43431 proteins, respectively. These genes were expressed in vitro and their initiation codons verified by deletion analysis. Tn5–751 had inserted near the centre of the exeE gene in the L1.97 strain. Subclones of the Kpnl 4.1 kb fragment which contained only the exeE gene fully complemented the mutation, indicating that its function is required both for extracellular secretion and outer membrane assembly. ExeE and ExeF are highly similar to other proteins which have been shown to be involved in extracellular secretion, suggesting that an additional export apparatus beyond that required for inner membrane translocation may be part of the physiology of many Gram‐negative bacteria.