6RMT

Crystal structure of disulphide-linked human C3d dimer

Summary for 6RMT

• Entry DOI: 10.2210/pdb6rmt/pdb
• Descriptor: Complement C3, CHLORIDE ION (3 entities in total)
• Functional Keywords: complement, innate immunity, immune system
• Biological source: Homo sapiens (Human)
• Total number of polymer chains: 2
• Total formula weight: 69699.44

Authors

Wahid, A.A.,van den Elsen, J.M.H.,Crennell, S.J. (deposition date: 2019-05-07, release date: 2020-11-18, Last modification date: 2024-10-16)

Primary citation

Wahid, A.A.,Dunphy, R.W.,Macpherson, A.,Gibson, B.G.,Kulik, L.,Whale, K.,Back, C.,Hallam, T.M.,Alkhawaja, B.,Martin, R.L.,Meschede, I.,Laabei, M.,Lawson, A.D.G.,Holers, V.M.,Watts, A.G.,Crennell, S.J.,Harris, C.L.,Marchbank, K.J.,van den Elsen, J.M.H.
Insights Into the Structure-Function Relationships of Dimeric C3d Fragments.
Front Immunol, 12:714055-714055, 2021

PubMed Abstract: Cleavage of C3 to C3a and C3b plays a central role in the generation of complement-mediated defences. Although the thioester-mediated surface deposition of C3b has been well-studied, fluid phase dimers of C3 fragments remain largely unexplored. Here we show C3 cleavage results in the spontaneous formation of C3b dimers and present the first X-ray crystal structure of a disulphide-linked human C3d dimer. Binding studies reveal these dimers are capable of crosslinking complement receptor 2 and preliminary cell-based analyses suggest they could modulate B cell activation to influence tolerogenic pathways. Altogether, insights into the physiologically-relevant functions of C3d(g) dimers gained from our findings will pave the way to enhancing our understanding surrounding the importance of complement in the fluid phase and could inform the design of novel therapies for immune system disorders in the future.

PubMed: 34434196
DOI: 10.3389/fimmu.2021.714055

Experimental method

X-RAY DIFFRACTION (2 Å)