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Major outer membrane protein in Salmonella typhimurium induced by maltose
Abstract:
A maltose-induced major outer membrane protein (the 44K protein) is demonstrated in Salmonella typhimurium. This protein resembles the lambda receptor of Escherichia coli in its location, induction properties, apparent molecular weight, and association with the peptidoglycan layer of the cell wall. The 44K protein is missing in certain Salmonella Mal- mutants, which are also missing a protein analogous to the maltose-binding protein of E. coli. Thus, these mutants may be defective in the control of maltose genese in Salmonella. The proteins appear to be closely related, as indicated by cross-reaction of the Salmonella protein with the antiserum raised against the lambda receptor; however, they are not identical, since the peptide patterns obtained after limited proteolysis are completely different. Bacteriophage lambda does not use the 44K protein as a receptor.
Insights
Salmonella typhimurium produces a 44K outer membrane protein induced by maltose, similar to E. coli's lambda receptor. This protein is absent in certain Salmonella mutants, suggesting defects in maltose gene regulation.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial genetics
Background:
- Salmonella typhimurium possesses a maltose-inducible outer membrane protein, termed 44K protein.
- This protein shares characteristics with the lambda receptor found in Escherichia coli, including location and molecular weight.
Purpose of the Study:
- To characterize the maltose-induced 44K protein in Salmonella typhimurium.
- To investigate the relationship between the 44K protein and maltose metabolism in Salmonella.
- To compare the 44K protein with the lambda receptor of Escherichia coli.
Main Methods:
- Analysis of outer membrane proteins in Salmonella typhimurium.
- Comparison of protein properties (location, induction, molecular weight, cell wall association) with E. coli lambda receptor.
- Genetic analysis of Salmonella Mal- mutants.
- Immunological cross-reactivity studies using antiserum against the lambda receptor.
- Limited proteolysis to compare peptide patterns.
Main Results:
- A maltose-inducible 44K major outer membrane protein was identified in Salmonella typhimurium.
- This protein is absent in specific Salmonella Mal- mutants lacking a maltose-binding protein analog.
- The Salmonella 44K protein cross-reacts with antiserum against the E. coli lambda receptor but has distinct peptide patterns.
- Bacteriophage lambda does not utilize the Salmonella 44K protein as a receptor.
Conclusions:
- The 44K protein is involved in maltose utilization in Salmonella typhimurium.
- Salmonella Mal- mutants may have regulatory defects in maltose genes.
- While related, the Salmonella 44K protein and E. coli lambda receptor are distinct entities.