3j24
CryoEM reconstruction of complement decay-accelerating factor
Structural highlights
FunctionDAF_HUMAN This protein recognizes C4b and C3b fragments that condense with cell-surface hydroxyl or amino groups when nascent C4b and C3b are locally generated during C4 and c3 activation. Interaction of daf with cell-associated C4b and C3b polypeptides interferes with their ability to catalyze the conversion of C2 and factor B to enzymatically active C2a and Bb and thereby prevents the formation of C4b2a and C3bBb, the amplification convertases of the complement cascade.[1] Publication Abstract from PubMedThe coxsackievirus-adenovirus receptor (CAR) and decay-accelerating factor (DAF) have been identified as cellular receptors for coxsackievirus B3 (CVB3). The first described DAF-binding isolate was obtained during passage of the prototype strain, Nancy, on rhabdomyosarcoma (RD) cells, which express DAF but very little CAR. Here, the structure of the resulting variant, CVB3-RD, has been solved by X-ray crystallography to 2.74A and a cryo-electron microscopy reconstruction of CVB3-RD complexed with DAF has been refined to 9.0A. This new high resolution structure permits us to correct an error in our previous view of DAF-virus interactions, providing a new footprint of DAF that bridges two adjacent protomers. The contact sites between virus and DAF clearly encompass CVB3-RD residues recently shown to be required for binding to DAF; these residues interact with DAF short consensus repeat (SCR)2, which is known to be essential for virus binding. Based on the new structure, the mode of DAF interaction with CVB3 differs significantly from the mode reported for DAF binding to echoviruses. The crystal structure of a coxsackievirus B3-RD variant, and a refined 9A cryoEM reconstruction of the virus complexed with decay accelerating factor (DAF), provide a new footprint of DAF onto the virus surface.,Yoder JD, Cifuente JO, Pan J, Bergelson JM, Hafenstein S J Virol. 2012 Sep 12. PMID:22973031[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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