Factor I can cleave C3b into C3c and C3d, the latter of which plays a role in enhancing B cell responses. In the alternative complement pathway, C3 is cleaved by C3bBb, another form of C3-convertase composed of activated forms of C3 (C3b) and factor B (Bb).

This Review provides a concise classification, summary, and interpretation of the more than 50 unique crystal structure determinations for human C3. It also highlights other salient features of C3 structure that were made possible through solution-based methods, including Hydrogen/Deuterium Exchange and Small Angle X-ray Scattering.

C3b is the larger of two elements formed by the cleavage of complement component 3, and is considered an important part of the innate immune system. C3b is potent in opsonization: tagging pathogens, immune complexes (antigen - antibody), and apoptotic cells for phagocytosis.

Dec 12, 2006 · C3 plays a central role in the activation of the complement system. Its processing by C3 convertase is the central reaction in both classical and alternative complement pathways. After activation C3b can bind covalently, via its reactive thioester, to cell surface carbohydrates or immune aggregates.

Sep 22, 2005 · Activation of component C3 (1,641 residues) is central to the three complement pathways and results in inflammation and elimination of self and non-self targets. Here we present crystal...

In our review, we look at the complement system as an archetype of a preformed mediator of host defense and show how nature industriously and elegantly uses a single molecular scaffold, i.e. complement component C3, to achieve exceptional versatility in coordinating defense responses.

C3 is the central effector molecule of the complement system, mediating its multiple functions through different binding sites and their corresponding receptors. We will introduce the C3 forms (native C3, C3 [H 2 O], and intracellular C3), the C3 fragments C3a, C3b, iC3b, and C3dg/C3d, and the C3 expression sites.

C3 is the central effector molecule of the complement system, mediating its multiple functions through different binding sites and their corresponding receptors. We will introduce the C3 forms (native C3, C3 [H 2 O], and intracellular C3), the C3 fragments C3a, C3b, iC3b, and C3dg/C3d, and the C3 expression sites.

2 days ago · Currently known sources of intracellular C3 Subcellular organelles Nucleus Cytoplasm ER C3b C3D C3 Met Met C3 (a) (b) (c) (d) C3 C3b C3b C3 C3 (e) (f) (g) Autophagosomes C3D C3 C3 mRNA C3 lacking signal peptide C3 (H2O)* * * C3 C an on ic al se cr et io n Jo urn al Pre- pro of Figure 4.

Oct 15, 2006 · Here we present a structure of C3b that reveals a marked loss of secondary structure in the CUB (for ‘complement C1r/C1s, Uegf, Bmp1’) domain, which together with the resulting translocation ...