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

Ana G C Neves-Ferreira1, Carlos M de Andrade, Marcos A Vannier-Santos

  • 1Departamento de Fisiologia e Farmacodinâmica, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.

The Protein Journal
|April 30, 2004
PubMed

Insights

The primary structure of Omp-28, a protein from Salmonella enterica serovar typhi, was fully determined. This outer membrane protein is homologous to proteins found in other bacteria like E. coli and Y. pestis.

Area of Science:

  • Microbiology
  • Proteomics
  • Structural Biology

Background:

  • Omp-28 is a protein isolated from Salmonella enterica serovar typhi.
  • Its function and structural characteristics require detailed investigation.

Purpose of the Study:

  • To elucidate the complete primary structure of Omp-28.
  • To identify homologous proteins in other bacterial species.
  • To determine the localization of Omp-28 within the bacterium.

Main Methods:

  • Mass spectrometry (MALDI-TOF MS) for molecular mass determination.
  • Protein sequencing techniques including Edman degradation, CNBr cleavage, and enzymatic hydrolysis (Glu-C, Asp-N).
  • Peptide isolation via SDS-PAGE, electroblotting, and RP-HPLC.
  • Bioinformatic analysis of homologous sequences and secondary structure prediction.
  • Immunogold cytochemistry for protein localization.

Main Results:

  • The subunit molecular mass of Omp-28 was determined to be 9,632 Da.
  • The complete primary amino acid sequence of Omp-28 was elucidated.
  • The determined sequence is identical to the putative periplasmic transport protein in S. enterica serovar typhimurium and a drug-resistant S. enterica serovar typhi.
  • Homologous protein sequences were identified in Escherichia coli and Yersinia pestis.
  • Immunogold cytochemistry confirmed Omp-28 is located on the bacterium's outer membrane.

Conclusions:

  • The study successfully determined the complete primary structure of Omp-28.
  • Omp-28 is an outer membrane protein conserved across several bacterial species, including pathogenic ones.
  • The findings provide a foundation for further functional and structural studies of Omp-28 and its homologs.

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