Recombinant Human Hyaluronan and Proteoglycan Link Protein 4 (HAPLN4) is produced in E. coli and spans the complete mature protein sequence from amino acids 30 to 402. The protein carries an N-terminal 10xHis-tag for easier purification and detection. SDS-PAGE analysis shows purity levels above 85%, which appears to provide reliable performance for research work.
HAPLN4 likely plays a crucial role in stabilizing how hyaluronic acid and proteoglycans interact within the extracellular matrix. It seems particularly important for maintaining the structural integrity of cartilage and neural tissues. Research into HAPLN4's molecular pathways may prove essential for understanding how tissues develop and repair themselves.
Potential Applications
Note: The applications listed below are based on what we know about this protein's biological functions, published research, and experience from experts in the field. However, we haven't fully tested all of these applications ourselves yet. We'd recommend running some preliminary tests first to make sure they work for your specific research goals.
Human HAPLN4 is an extracellular matrix protein that requires complex disulfide bond formation and proper folding for its structural and functional roles in organizing proteoglycan-hyaluronan complexes. The E. coli expression system cannot perform the necessary post-translational modifications (particularly proper disulfide bonding) that are critical for this protein's native conformation. While the protein may be soluble, it is highly unlikely to achieve the correct three-dimensional structure needed for functional activity. The probability of correct folding is low, and biological activity cannot be assumed.
1. Antibody Development and Validation
This recombinant HAPLN4 serves as an excellent immunogen for generating antibodies against linear epitopes of the protein. The full-length mature sequence ensures comprehensive epitope coverage. However, antibodies produced against this bacterially expressed protein may not efficiently recognize conformational epitopes on the native, properly folded HAPLN4 found in tissues, as they will primarily target linear sequences.
2. ELISA-Based Quantitative Assays
This protein is well-suited as a standard for quantitative ELISA assays to measure immunoreactive HAPLN4 levels. The assay depends on antibody binding to linear epitopes, so the protein's folding state is less critical. The His-tag facilitates consistent immobilization for reliable standard curve generation.
Final Recommendation & Action Plan
The protein can be reliably used for Application 1 (Antibody Development) and Application 2 (as an ELISA standard). Extracellular matrix protein interactions are highly dependent on precise three-dimensional conformation. Functional extracellular matrix studies require properly folded, active proteins. This bacterially expressed variant cannot recapitulate native HAPLN4 function.
