1a3r
FAB FRAGMENT (ANTIBODY 8F5) COMPLEXED WITH PEPTIDE FROM HUMAN RHINOVIRUS (SEROTYPE 2) VIRAL CAPSID PROTEIN VP2 (RESIDUES 156-170)FAB FRAGMENT (ANTIBODY 8F5) COMPLEXED WITH PEPTIDE FROM HUMAN RHINOVIRUS (SEROTYPE 2) VIRAL CAPSID PROTEIN VP2 (RESIDUES 156-170)
Structural highlights
Function[POLG_HRV2] Capsid proteins VP1, VP2, VP3 and VP4 form a closed capsid enclosing the viral positive strand RNA genome. VP4 lies on the inner surface of the protein shell formed by VP1, VP2 and VP3. All the three latter proteins contain a beta-sheet structure called beta-barrel jelly roll. Together they form an icosahedral capsid (T=3) composed of 60 copies of each VP1, VP2, and VP3, with a diameter of approximately 300 Angstroms. VP1 is situated at the 12 fivefold axes, whereas VP2 and VP3 are located at the quasi-sixfold axes. The capsid interacts with human VLDLR to provide virion attachment to target cell. This attachment induces virion internalization predominantly through clathrin-mediated endocytosis. VP4 and VP1 subsequently undergo conformational changes leading to the formation of a pore in the endosomal membrane, thereby delivering the viral genome into the cytoplasm.[1] [2] VP0 precursor is a component of immature procapsids (By similarity).[3] [4] Protein 2A is a cysteine protease that is responsible for the cleavage between the P1 and P2 regions. It cleaves the host translation initiation factor EIF4G1, in order to shut down the capped cellular mRNA transcription.[5] [6] Protein 2B affects membrane integrity and cause an increase in membrane permeability (By similarity).[7] [8] Protein 2C associates with and induces structural rearrangements of intracellular membranes. It displays RNA-binding, nucleotide binding and NTPase activities (By similarity).[9] [10] Protein 3A, via its hydrophobic domain, serves as membrane anchor (By similarity).[11] [12] 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).[13] [14] RNA-directed RNA polymerase 3D-POL replicates genomic and antigenomic RNA by recognizing replications specific signals (By similarity).[15] [16] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe three-dimensional structure of the complex between the Fab fragment of an anti-human rhinovirus neutralizing antibody (8F5) and a cross-reactive synthetic peptide from the viral capsid protein VP2 has been determined at 2.5 A resolution by crystallographic methods. The refinement is presently at an R factor of 0.18 and the antigen-binding site and viral peptide are well defined. The peptide antigen adopts a compact fold by two tight turns and interacts through hydrogen bonds, some with ionic character, and van der Waals contacts with antibody residues from the six hypervariable loops as well as several framework amino acids. The conformation adopted by the peptide is closely related to the corresponding region of the viral protein VP2 on the surface of human rhinovirus 1A whose three-dimensional structure is known. Implications for the cross-reactivity between peptides and the viral capsid are discussed. The peptide-antibody interactions, together with the analysis of mutant viruses that escape neutralization by 8F5 suggest two different mechanisms for viral escape. The comparison between the complexed and uncomplexed antibody structures shows important conformational rearrangements, especially in the hypervariable loops of the heavy chain. Thus, it constitutes a clear example of the 'induced fit' molecular recognition mechanism. Crystal structure of a human rhinovirus neutralizing antibody complexed with a peptide derived from viral capsid protein VP2.,Tormo J, Blaas D, Parry NR, Rowlands D, Stuart D, Fita I EMBO J. 1994 May 15;13(10):2247-56. PMID:8194515[17] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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