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Diversity of the P2 protein among nontypeable Haemophilus influenzae isolates
1Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri.
Abstract:
The genes for outer membrane protein P2 of four nontypeable Haemophilus influenzae strains were cloned and sequenced. The derived amino acid sequences were compared with the outer membrane protein P2 sequence from H. influenzae type b MinnA and the sequences of P2 from three additional nontypeable H. influenzae strains. The sequences were 76 to 94% identical. The sequences had regions with considerable variability separated by regions which were highly conserved. The variable regions mapped to putative surface-exposed loops of the protein.
Insights
Outer membrane protein P2 genes from nontypeable Haemophilus influenzae strains show 76-94% sequence identity. Variable regions in these protein sequences likely correspond to surface-exposed loops.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Nontypeable Haemophilus influenzae (NTHi) are significant human pathogens.
- Outer membrane proteins (OMPs) are crucial for bacterial structure and interaction with the host.
- Protein P2 is a major outer membrane protein in H. influenzae.
Purpose of the Study:
- To analyze the genetic and sequence variability of the outer membrane protein P2 gene in NTHi.
- To compare NTHi P2 sequences with those from other H. influenzae strains.
- To identify conserved and variable regions within the P2 protein.
Main Methods:
- Cloning and sequencing of the outer membrane protein P2 gene from four NTHi strains.
- Bioinformatic analysis and comparison of derived amino acid sequences.
- Sequence alignment to identify regions of conservation and variability.
Main Results:
- The P2 gene sequences from NTHi strains exhibited 76% to 94% identity.
- Highly conserved regions were interspersed with regions of considerable variability.
- Variable regions were mapped to putative surface-exposed loops of the P2 protein.
Conclusions:
- The P2 protein sequence in NTHi displays significant variability, particularly in surface-exposed loop regions.
- Understanding this variability is important for studying NTHi pathogenesis and developing potential therapeutics or vaccines.
- Conserved regions may represent functionally important domains of the protein.