1LY2

Crystal structure of unliganded human CD21 SCR1-SCR2 (Complement receptor type 2)

Summary for 1LY2

• Entry DOI: 10.2210/pdb1ly2/pdb
• Descriptor: complement receptor type 2, 2-acetamido-2-deoxy-beta-D-glucopyranose (3 entities in total)
• Functional Keywords: complement receptor; epstein barr virus; regulator of complement activation; short consensus repeat; viral receptor; complement control protein, immune system
• Biological source: Homo sapiens (human)
• Cellular location: Membrane; Single-pass type I membrane protein: P20023
• Total number of polymer chains: 1
• Total formula weight: 14698.73

Authors

Prota, A.E.,Sage, D.R.,Stehle, T.,Fingeroth, J.D. (deposition date: 2002-06-06, release date: 2002-07-05, Last modification date: 2024-11-20)

Primary citation

Prota, A.E.,Sage, D.R.,Stehle, T.,Fingeroth, J.D.
The crystal structure of human CD21: Implications for Epstein-Barr virus and C3d binding.
Proc.Natl.Acad.Sci.USA, 99:10641-10646, 2002

PubMed Abstract: Human complement receptor type 2 (CD21) is the cellular receptor for Epstein-Barr virus (EBV), a human tumor virus. The N-terminal two short consensus repeats (SCR1-SCR2) of the receptor interact with the EBV glycoprotein gp350/220 and also with the natural CD21 ligand C3d. Here we present the crystal structure of the CD21 SCR1-SCR2 fragment in the absence of ligand and demonstrate that it is able to bind EBV. Based on a functional analysis of wild-type and mutant CD21 and molecular modeling, we identify a likely region for EBV attachment and demonstrate that this region is not involved in the interaction with C3d. A comparison with the previously determined structure of CD21 SCR1-SCR2 in complex with C3d shows that, in both cases, CD21 assumes compact V-shaped conformations. However, our analysis reveals a surprising degree of flexibility at the SCR1-SCR2 interface, suggesting interactions between the two domains are not specific. We present evidence that the V-shaped conformation is induced by deglycosylation of the protein, and that physiologic glycosylation of CD21 would result in a more extended conformation, perhaps with additional epitopes for C3d binding.

PubMed: 12122212
DOI: 10.1073/pnas.162360499

Experimental method

X-RAY DIFFRACTION (1.8 Å)