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The nucleotide sequence of a putative membrane transport gene from Clostridium perfringens
Abstract:
A gene from Clostridium perfringens encoding a highly hydrophobic polypeptide of M(r) = 30,698 was cloned and sequenced. The polypeptide showed similarities with the inner membrane proteins of binding protein-dependent transport systems of the gram negative enterobacteria. The sequence homology to the UgpE and MalG proteins of Escherichia coli was 27.6%, or 60.4 and 52.2%, respectively, taking into account the conservative amino acid changes. The polypeptide contained the EAA---G---------(I/V)-LP motif of the gram negative transport proteins. This motif may thus be very old, as clostridia and E. coli separated some 1.5 x 10(9) years ago. The similarities suggest a common evolutionary origin of these genes.
Insights
Researchers cloned a Clostridium perfringens gene encoding a hydrophobic protein similar to inner membrane transport proteins in E. coli. This suggests ancient evolutionary origins for these essential bacterial transport systems.
Area of Science:
- Microbiology
- Molecular Biology
- Evolutionary Biology
Background:
- Inner membrane proteins are crucial for transport systems in bacteria.
- Gram-negative bacteria utilize binding protein-dependent transport systems.
- Clostridium perfringens is a Gram-positive bacterium with distinct cellular structures.
Purpose of the Study:
- To clone and sequence a gene from Clostridium perfringens.
- To characterize the encoded polypeptide and its potential function.
- To investigate evolutionary relationships between bacterial transport proteins.
Main Methods:
- Gene cloning and DNA sequencing from Clostridium perfringens.
- Bioinformatic analysis of the deduced amino acid sequence.
- Sequence homology comparisons with known bacterial proteins.
Main Results:
- A gene encoding a highly hydrophobic polypeptide (30,698 M(r)) was identified.
- The polypeptide exhibits sequence homology to inner membrane transport proteins of Gram-negative bacteria, specifically E. coli UgpE and MalG.
- A conserved transport protein motif (EAA---G---------(I/V)-LP) was found, suggesting ancient conservation.
Conclusions:
- The identified Clostridium perfringens protein shares evolutionary origins with Gram-negative bacterial transport proteins.
- The conserved motif indicates a very old evolutionary history for these transport systems.
- This finding sheds light on the early evolution of bacterial membrane transport mechanisms.