Related Experiment Videos
Complementary DNA sequence of rabbit CAP18--a unique lipopolysaccharide binding protein
J W Larrick1, J G Morgan, I Palings
1Genelabs Incorporated, Redwood City, CA 94063.
Biochemical and Biophysical Research Communications
|August 30, 1991
Summary
Researchers identified CAP18, a novel cationic protein from rabbit granulocytes. This protein binds lipopolysaccharide (LPS) and shows no homology to other known LPS-binding proteins, suggesting a unique antimicrobial mechanism.
Area of Science:
- Immunology
- Biochemistry
- Molecular Biology
Background:
- Rabbit granulocytes contain a novel 18 kDa cationic protein, CAP18.
- CAP18 was purified using an assay for lipopolysaccharide (LPS) agglutination.
- Its function and characteristics were previously unknown.
Purpose of the Study:
- To isolate and characterize the cDNA encoding CAP18.
- To determine the amino acid sequence and structural properties of CAP18.
- To compare CAP18 with other known LPS-binding proteins.
Main Methods:
- Oligonucleotide probe derived from N-terminal amino acid sequence.
- Screening of a rabbit bone marrow cDNA library.
- PCR amplification and sequence analysis.
Main Results:
- Isolated cDNA clones encoding CAP18.
- Deduced a 29-amino acid signal sequence and a 142-amino acid mature protein.
- Predicted molecular mass of 16.6 kDa and pI of 10, with no N-linked glycosylation sites.
- CAP18 sequence showed no homology to human BPI or rabbit LBP.
Conclusions:
- CAP18 is a novel LPS-binding protein with a unique structure.
- Its distinct sequence suggests a novel mechanism of LPS interaction.
- Further research is warranted to elucidate CAP18's specific antimicrobial functions.