structural model of human decay-accelerating factor bound to echovirus 7 from cryo-electron microscopy
[Q914E0_9ENTO] Protein 2C associates with and induces structural rearrangements of intracellular membranes. It displays RNA-binding, nucleotide binding and NTPase activities (By similarity).[SAAS:SAAS000199_004_016611] Protein 3C is a cysteine protease that generates mature viral proteins from the precursor polyprotein. In addition to its proteolytic activity, it binds to viral RNA, and thus influences viral genome replication. RNA and substrate bind co-operatively to the protease (By similarity).[SAAS:SAAS000199_004_042266] RNA-directed RNA polymerase 3D-POL replicates genomic and antigenomic RNA by recognizing replications specific signals (By similarity).[SAAS:SAAS000199_004_010047] [DAF_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.
Publication Abstract from PubMed
Echoviruses are enteroviruses that belong to Picornaviridae. Many echoviruses use decay-accelerating factor (DAF) as their cellular receptor. DAF is a glycosylphosphatidyl inositol-anchored complement regulatory protein found on most cell surfaces. It functions to protect cells from complement attack. The cryo-electron microscopy reconstructions of echovirus 7 complexed with DAF show that the DAF-binding regions are located close to the icosahedral twofold axes, in contrast to other enterovirus complexes where the viral canyon is the receptor binding site. This novel receptor binding position suggests that DAF is important for the attachment of viral particles to host cells, but probably not for initiating viral uncoating, as is the case with canyon-binding receptors. Thus, a different cell entry mechanism must be used for enteroviruses that bind DAF.
Structure of decay-accelerating factor bound to echovirus 7: a virus-receptor complex.,He Y, Lin F, Chipman PR, Bator CM, Baker TS, Shoham M, Kuhn RJ, Medof ME, Rossmann MG Proc Natl Acad Sci U S A. 2002 Aug 6;99(16):10325-9. Epub 2002 Jul 15. PMID:12119400
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.