2I6Q
Complement component C2a
Summary for 2I6Q
Entry DOI | 10.2210/pdb2i6q/pdb |
Related | 2I6S |
Descriptor | Complement C2a fragment, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-[alpha-L-fucopyranose-(1-6)]2-acetamido-2-deoxy-beta-D-glucopyranose, beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (7 entities in total) |
Functional Keywords | serine protease domain, von willebrand factor-a domain, hydrolase |
Biological source | Homo sapiens (human) |
Cellular location | Secreted: P06681 |
Total number of polymer chains | 1 |
Total formula weight | 59999.76 |
Authors | Milder, F.J.,Raaijmakers, H.C.A.,Vandeputte, D.A.A.,Schouten, A.,Huizinga, E.G.,Romijn, R.A.,Hemrika, W.,Roos, A.,Daha, M.R.,Gros, P. (deposition date: 2006-08-29, release date: 2006-10-17, Last modification date: 2024-11-06) |
Primary citation | Milder, F.J.,Raaijmakers, H.C.,Vandeputte, M.D.,Schouten, A.,Huizinga, E.G.,Romijn, R.A.,Hemrika, W.,Roos, A.,Daha, M.R.,Gros, P. Structure of complement component c2a: implications for convertase formation and substrate binding. Structure, 14:1587-1597, 2006 Cited by PubMed Abstract: C2a provides the catalytic center to the convertase complexes of the classical and lectin-binding pathways of complement activation. We determined two crystal structures of full-length C2a, with and without a pseudo ligand bound. Both structures reveal a near-active conformation of the catalytic center of the serine protease domains, while the von Willebrand factor A-type domains display an intermediate activation state of helix alpha7 with an open, activated metal-ion-dependent adhesion site. The open adhesion site likely serves to enhance the affinity for the ligand C4b, similar to "inside-out" signaling in integrins. Surprisingly, the N-terminal residues of C2a are buried in a crevice near helix alpha7, indicative of a structural switch between C2 and C2a. Extended loops on the protease domain possibly envelop the protruding anaphylatoxin domain of the substrate C3. Together with a putative substrate-induced completion of the oxyanion hole, this may contribute to the high substrate specificity of the convertases. PubMed: 17027507DOI: 10.1016/j.str.2006.08.008 PDB entries with the same primary citation |
Experimental method | X-RAY DIFFRACTION (2.1 Å) |
Structure validation
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