Sequence and transcriptional start site of the Pseudomonas aeruginosa outer membrane porin protein F gene

Abstract

Porin F is one of the major proteins of the outer membrane of Pseudomonas aeruginosa. It forms water-filled pores of variable size. Porin F is a candidate for a vaccine against P. aeruginosa because it antigenically cross-reacts in all serotype strains of the International Antigenic Typing Scheme. We have isolated the gene for porin F from a lambda EMBL3 bacteriophage library by using oligodeoxynucleotide hybridization probes and have determined its nucleotide sequence. Different peptide sequences obtained from isolated porin F confirmed the deduced protein sequence. The mature protein consists of 326 amino acid residues and has a molecular weight of 35,250. The precursor contains an N-terminal signal peptide of 24 amino acid residues. S1 protection and primer extension experiments, together with Northern (RNA) blots, indicate that the mRNA coding for porin F is monocistronic with short untranslated regions of about 58 bases at the 5' end and about 47 bases at the 3' end. The sequences in the -10 and -35 regions upstream of the transcriptional start site are closely related to the Escherichia coli promoter consensus sequences, which explains why the porin F gene is expressed in E. coli under the control of its own promoter. The amino acid sequence of porin F is not homologous to the different E. coli porins OmpF, OmpC, LamB, and PhoE. On the other hand, a highly homologous region of 30 amino acids between the OmpA proteins of different enteric bacteria and porin F of P. aeruginosa was detected. The core region of the homology to E. coli OmpA had 11 of 12 amino acid residues in common.

Conservation of the gene for outer membrane protein OprF in the family Pseudomonadaceae: sequence of the Pseudomonas syringae oprF gene

“…The overall G+C content of the P. syringae oprF gene was 55.3%, which is lower than the 60.2% value for the P. aeruginosa oprF gene (12), reflecting the respective G+C contents of these species. The difference was apparently due to a lower bias for G+C in the third position of codons of P. syringae oprF (61.7%) compared with that of P. aeruginosa oprF (78.2%).…”

“…The P. aeruginosa oprF gene sequence was previously determined by Duchene et al (12). Its size (1,050 bp) was similar to that of the above-described P. syringae oprF gene.…”

“…4, Table 3). In particular, the carboxy-terminal half of P. aeruginosa OprF, which had been previously shown to have homology to the equivalent portion of the E. coli OmpA protein (4,12,38), was highly similar to the carboxy terminus of P. syringae OprF with 85% identity and 10% conservative substitutions.…”

“…Its size (1,050 bp) was similar to that of the above-described P. syringae oprF gene. Comparison of the sequences revealed that a SalI site was similarly placed in both genes in that there was conservation of the special features of the amino acid sequence flanking this region (notably four closely spaced cysteine residues that form two disulfide bonds (16) and an alanineproline-rich region [12]). …”

Localization of alg, opr, phn, pho, 4.5S RNA, 6S RNA, tox, trp, and xcp genes, rrn operons, and the chromosomal origin on the physical genome map of Pseudomonas aeruginosa PAO

“…In E. coli, the positive regulatory gene phoB is part of the pho regulon which responds to phosphate limitation (41). The structural genes for two major outer membrane proteins F and I, oprF (14) and oprI (13), as well as the structural and regulatory genes for exotoxin A expression, toxA (21)(22)(23) and toxR (24,48), are located outside the auxotroph-rich region of the chromosome. The distance between toxA and toxR is at least 150 kb.…”