3ERB

The Crystal Structure of C2b, a Fragment of Complement Component C2 produced during C3-convertase Formation

Summary for 3ERB

• Entry DOI: 10.2210/pdb3erb/pdb
• Related: 2ODP 2ODQ
• Descriptor: Complement C2 (2 entities in total)
• Functional Keywords: complement component c2b, c3/c5 convertase, complement control protein (ccp), short consensus repeat(scr), sushi domain, human complement system, complement second component c2, complement pathway, disease mutation, glycoprotein, hydrolase, immune response, innate immunity, polymorphism, protease, secreted, serine protease, sushi
• Biological source: Homo sapiens (Human)
• Cellular location: Secreted: P06681
• Total number of polymer chains: 1
• Total formula weight: 23707.52

Authors

Narayan, S.V.L.,Krishnan, V. (deposition date: 2008-10-01, release date: 2009-03-10, Last modification date: 2024-10-30)

Primary citation

Krishnan, V.,Xu, Y.,Macon, K.,Volanakis, J.E.,Narayana, S.V.
The structure of C2b, a fragment of complement component C2 produced during C3 convertase formation
Acta Crystallogr.,Sect.D, 65:266-274, 2009

PubMed Abstract: The second component of complement (C2) is a multi-domain serine protease that provides catalytic activity for the C3 and C5 convertases of the classical and lectin pathways of human complement. The formation of these convertases requires the Mg(2+)-dependent binding of C2 to C4b and the subsequent cleavage of C2 by C1s or MASP2, respectively. The crystal structure of full-length C2 is not yet available, although the structure of its C-terminal catalytic segment C2a has been determined. The crystal structure of the N-terminal segment C2b of C2 determined to 1.8 A resolution presented here reveals the arrangement of its three CCP domains. The domains are arranged differently compared with most other CCP-domain assemblies, but their arrangement is similar to that found in the Ba part of the full-length factor B structure. The crystal structures of C2a, C2b and full-length factor B are used to generate a model for C2 and a discussion of the domain association and possible interactions with C4b during formation of the C4b-C2 complex is presented. The results of this study also suggest that upon cleavage by C1s, C2a domains undergo conformational rotation while bound to C4b and the released C2b domains may remain folded together similar to as observed in the intact protein.

PubMed: 19237749
DOI: 10.1107/S0907444909000389

Experimental method

X-RAY DIFFRACTION (1.8 Å)