Related Experiment Videos
Comparative analyses of pentraxins: implications for protomer assembly and ligand binding
N Srinivasan1, H E White, J Emsley
1Laboratory of Molecular Biology, Birkbeck College, University of London, UK.
Structure (London, England : 1993)
|November 15, 1994
Summary
Structural analysis of pentraxins reveals conserved features and key differences. Human serum amyloid P component (SAP) structure aids comparison, showing similar calcium-binding but distinct ligand specificities due to sequence variations.
Area of Science:
- Biochemistry
- Structural Biology
- Immunology
Background:
- Pentraxins are plasma proteins with pentameric structure and calcium-dependent ligand binding.
- Human serum amyloid P component (SAP) crystal structure enables comparative analysis of the pentraxin family.
Purpose of the Study:
- To compare sequences, tertiary structures, and quaternary arrangements of SAP with other pentraxins.
- To elucidate the structural basis for differential ligand specificities and quaternary structures within the pentraxin family.
Main Methods:
- Comparative sequence analysis.
- Tertiary structure comparison based on crystal structures.
- Quaternary arrangement analysis.
Main Results:
- SAP, human C-reactive protein (CRP), Syrian hamster SAP (HSAP), and Limulus polyphemus CRP (LIM) share beta-jelly roll topology and a hydrophobic core.
- Minor differences exist in calcium-coordinating residues.
- Sequence variations in the hydrophobic pocket correlate with differing ligand specificities.
Conclusions:
- Calcium-mediated ligand binding is structurally similar across CRP, HSAP, and LIM, mirroring SAP.
- Sequence differences in hydrophobic pockets dictate distinct ligand specificities among homologous pentraxins.
- Insertions and deletions explain the hexameric quaternary structure of LIM, contrasting with other pentraxins.