Nucleotide sequence of the gene ompA coding the outer membrane protein II * of Escherichia coli K-12 (original) (raw)
Related papers
MGG Molecular & General Genetics, 1982
The regulatory region of the ompA gene from Escherichia coIi has been characterized by biochemical and genetic approaches. Two overlapping promoters, P1 and P2, organized in that order with respect to the ompA coding sequence, were identified and it was found that ompA possesses an unusually long leader region. Both P1 and P2 were active in an in vitro transcription system although S1 mapping analysis of the ompA mRNA made in vivo showed that P2 was mainly responsible for transcription of the gene. Confirmation of this was obtained by studying down-promoter mutants of ompA cloned in pSC101. These mutants were classified into two groups, deletions and insertions. The deletions, which were caused by the IS102 insertion element found in pSCI01 removed the -35 regions of both P1 and P2. However, since P2 was distally situated with respect to the IS element it was less extensively damaged and it is proposed that the residual P2 sequence is responsible for the low level of expression observed. In addition to an IS102 insertion in the promoter region four ISI insertion mutants were characterized. These had integrated at different positions in the ompA leader region and were all incompletely polar.
Primary structure of toetolCgene that codes for an outer membrane protein ofEscherichia coliK12
Nucleic Acids Research, 1983
We present the nucleotide sequence of the tolC gene of Escherichia coll K12, and the amlno acid sequence of the TolC protein (an outer membrane protein) as deduced from it. The mature TolC protein comprises 467 amino acid residues, and, as previously reported (1), a signal sequence of 22 amino acid residues is attached to the N-terminus. The C-terminus of the gene is followed by a stem-loop structure (8 base pair stem, 4 base loop) which may be a rho-independent termination signal. The codon usage of the gene is nonrandom; the major isoaccepting species of tRNA are preferentially utilised, or, among synonomous codons recognized by the same tRNA, those codons are used which can interact better with the anticodon (2,3). In contrast to the codon usage for other outer membrane proteins of E. coli (4) the rare arglnine codons AGA and AGG are used once and twice respectively.
Biochimie, 1990
Various monoclonal antibodies (MoF) directed against cell-surface-exposed epitopes of OmpF, one major outer membrane pore protein of Escherichia coil B and K-12, have been used to study the assembly and the topology of the protein. Thi-~ paper firstly describes the characterization of the OmpF epitopes recognized by the various monoclonal antibodies. A comparison between OmpC, OmpF and PhoE porins with respect to their primary amino acid sequence and their cell-surface exposed regions allows u~ io propose a rough model including 2 antigenic sites. The second part is focused on the assembly of the OmpF protein in the outer membrane. Various forms, precursor, unussembled monomer, metastable oligomer (pre-trimer) and trimer are detected with immunological probes directed against OmpF during a kinetic analysis of the process. The requirement for a concomitant lipid synthesis during the trimerization has been demonstrated by investigating the presence of a specific native epitope. The role of lipopolysaccharide during the stabilization of the conformation is discussed with regard to the various steps of assembly.