Like many other S100 proteins, S100A1 can exist as either a hetero or homodimer. Protein nuclear magnetic resonance spectroscopy structural information on the homodimeric form of this protein shows that each monomer is quite helical, and contains two EF-hand calcium-binding loops; an 'S100' EF hand in the N-terminus and a canonical EF-hand in the C-terminus. These domains are linked by a 'hinge' region, which exists as a random coil. Both EF-hands bind calcium, although the real EF-hand has a significantly higher affinity (with a dissociation constant of roughly 20 micromolar). The two calcium-binding regions neighbor each other in three dimensional space, and are connected to each other through a short beta sheet region (residues 27–29 and 68–70).
The S100A1 homodimer is high affinity (nanomolar range or tighter), and is formed through hydrophobic packing of an X-type 4-helix bundle created between helices 1, 1', 4, and 4'.
The most accurate high-resolution solution structure of human apo-S100A1 protein (PDB accession code: 2L0P) has been determined by means of NMR spectroscopy in 2011.
more about:
Anti-S-100A1 (S100 calcium-binding protein A1) prices
from:
Elisa assay kits
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