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Overlapping functions of components of a bacterial Sec‐independent protein export pathway
Author(s) -
Sargent Frank,
Bogsch Erik G.,
Stanley Nicola R.,
Wexler Margaret,
Robinson Colin,
Berks Ben C.,
Palmer Tracy
Publication year - 1998
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/17.13.3640
Subject(s) - biology , escherichia coli proteins , bacterial protein , microbiology and biotechnology , computational biology , genetics , bacteria
We describe the identification of two Escherichia coli genes required for the export of cofactor‐containing periplasmic proteins, synthesized with signal peptides containing a twin arginine motif. Both gene products are homologous to the maize HCF106 protein required for the translocation of a subset of lumenal proteins across the thylakoid membrane. Disruption of either gene affects the export of a range of such proteins, and a complete block is observed when both genes are inactivated. The Sec protein export pathway was unaffected, indicating the involvement of the gene products in a novel export system. The accumulation of active cofactor‐containing proteins in the cytoplasm of the mutant strains suggests a role for the gene products in the translocation of folded proteins. One of the two HCF106 homologues is encoded by the first gene of a four cistron operon, tatABCD , and the second by an unlinked gene, tatE . A mutation previously assigned to the hcf106 homologue encoded at the tatABCD locus, mttA , lies instead in the tatB gene.