Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Human complement protein C9 is a calcium binding protein. Structural and functional implications.

N M Thielens1, K Lohner, A F Esser

  • 1Department of Comparative and Experimental Pathology, University of Florida, Gainesville 32610.

The Journal of Biological Chemistry
|May 15, 1988
PubMed
Summary
This summary is machine-generated.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Optimizing rapid solvent exchange preparation of multilamellar vesicles.

Chemistry and physics of lipids·2014
Same author

Use of X-ray scattering to aid the design and delivery of membrane-active drugs.

European biophysics journal : EBJ·2012
Same author

Genetic and structural analysis of MBL2 and MASP2 polymorphisms in south-eastern African children.

Tissue antigens·2009
Same author

Interaction of LL-37 with model membrane systems of different complexity: influence of the lipid matrix.

Biophysical journal·2008
Same author

How lipids influence the mode of action of membrane-active peptides.

Biochimica et biophysica acta·2007
Same author

Composition dependence of vesicle morphology and mixing properties in a bacterial model membrane system.

Biochimica et biophysica acta·2005
Same journal

Isotope-Edited ESEEM: A New Method for Probing Copper Binding Sites in Neurodegenerative Proteins.

The Journal of biological chemistry·2026
Same journal

Introduction to the Thematic Review Series on Intracellular Protein Degradation. The ubiquitous biology of intracellular protein degradation: a tribute to Alfred L. ("Fred") Goldberg.

The Journal of biological chemistry·2026
Same journal

Correction: Aromatic residue-rich amino-terminal segments of temporin L self-assemble into collagen-mimetic peptides with cell-adhesion properties.

The Journal of biological chemistry·2026
Same journal

YhbO is a DJ-1 family glyoxalase and α-oxoaldehyde hydratase that confers resistance to reactive carbonyl stress (112).

The Journal of biological chemistry·2026
Same journal

ARMH3 acts as a central scaffold at the Golgi/TGN through interactions with Arl5, GBF1, and PI4KB.

The Journal of biological chemistry·2026
Same journal

PAX8 controls proximal tubule epithelial identity and stress response through epigenetic modification of distal regulatory elements.

The Journal of biological chemistry·2026
See all related articles

Human complement protein C9 binds calcium, which is essential for its thermal stability. Removing calcium (Ca2+) leads to aggregation and loss of hemolytic activity, highlighting calcium's regulatory role.

Area of Science:

  • Biochemistry
  • Immunology
  • Structural Biology

Background:

  • Human complement protein C9 is a key component of the membrane attack complex.
  • The role of metal ions in C9 function and stability is not fully understood.

Purpose of the Study:

  • To investigate the binding of calcium (Ca2+) to human complement protein C9.
  • To determine the functional and structural consequences of calcium binding and removal.

Main Methods:

  • Equilibrium dialysis was used to measure Ca2+ binding affinity.
  • Ethylenediaminetetraacetic acid (EDTA) was used to chelate Ca2+.
  • Thermal stability and hemolytic activity assays were performed.
  • Ligand blotting identified the Ca2+ binding site.

Related Experiment Videos

Main Results:

  • Human C9 binds 1 mol of Ca2+ per mole of protein with a dissociation constant of 3 μM.
  • Calcium removal by EDTA decreases C9's thermal stability, leading to aggregation and loss of hemolytic activity upon heating.
  • Protein aggregation due to calcium removal can be prevented by stabilizing salts.
  • The Ca2+ binding site is located in the amino-terminal half of C9.
  • Calcium removal does not affect C9's hemolytic activity or binding to C8 or lipid vesicles at physiological temperatures.

Conclusions:

  • Bound calcium provides essential thermal stability to human complement protein C9.
  • Calcium may play a regulatory role in C9's membrane insertion function.
  • Further research is needed to elucidate the precise structural and functional role of Ca2+ in C9.