Complete amino acid sequence and location of Omp-28, an important immunogenic protein from Salmonella enterica serovar typhi

• Published in: The Protein Journal Vol. 23; no. 1; pp. 71 - 77
• Main Authors: Neves-Ferreira, Ana G C, de Andrade, Carlos M, Vannier-Santos, Marcos A, Perales, Jonas, Nascimento, Hilton J, da Silva Junior, José G
• Format: Journal Article
• Language: English
• Published: Netherlands Springer Nature B.V 01-01-2004
• Subjects: Alkylation; Amino Acid Sequence; Amino acids; Bacterial Outer Membrane Proteins - chemistry; Bacterial Outer Membrane Proteins - genetics; Bacterial Outer Membrane Proteins - immunology; Bacteriology; Cytochemistry; Deoxyribonucleic acid; DNA; Drug resistance; E coli; Gel electrophoresis; Genome, Bacterial; Gram-Negative Bacteria - genetics; Gram-Negative Bacteria - immunology; High-performance liquid chromatography; Homology; Immunogenicity; Liquid chromatography; Microbiology; Molecular Sequence Data; Multidrug resistance; Nucleotide sequence; Outer membrane proteins; Peptides; Protein Structure, Secondary; Protein transport; Proteins; Salmonella; Salmonella enterica; Salmonella typhi - genetics; Salmonella typhi - immunology; Salmonella typhi - ultrastructure; Sequence Analysis, Protein; Sequence Homology, Nucleic Acid; Sodium lauryl sulfate
• ISSN: 1572-3887; 1875-8355; 1573-4943
• DOI: 10.1023/B:JOPC.0000016260.03793.30

Omp-28 isolated from Salmonella enterica serovar typhi presented a subunit molecular mass of 9,632 Da by MALDI-TOF MS. It was denatured, S-alkylated, and 1) directly submitted to Edman sequencing, 2) cleaved with CNBr, and 3) hydrolyzed either with endoproteinase Glu-C or Asp-N. The major CNBr peptide containing the C-terminal portion of Omp-28 was isolated by tricine-SDS-PAGE and electroblotted whereas Omp-28 enzymatic peptides were isolated by C18-RP-HPLC. All peptides were sequenced. This approach allowed the elucidation of the complete primary structure of Omp-28. Its amino acid sequence is identical to that deduced from part of the DNA of the "putative periplasmic transport protein" of either S. enterica serovar typhimurium and a multiple drug resistant S. enterica serovar typhi. Omp-28 homologous protein sequences were also deduced from Escherichia coli and Yersinia pestis genomic DNA. All proteins had their secondary structures predicted. Immunogold cytochemistry indicated that Omp-28 is found on the bacterium outer membrane.