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Title | Near-Atomic Resolution Structure of a Highly Neutralizing Fab Bound to Canine Parvovirus. |
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Journal, issue, pages | J Virol, Vol. 90, Issue 21, Page 9733-9742, Year 2016 |
Publish date | Nov 1, 2016 |
Authors | Lindsey J Organtini / Hyunwook Lee / Sho Iketani / Kai Huang / Robert E Ashley / Alexander M Makhov / James F Conway / Colin R Parrish / Susan Hafenstein / |
PubMed Abstract | Canine parvovirus (CPV) is a highly contagious pathogen that causes severe disease in dogs and wildlife. Previously, a panel of neutralizing monoclonal antibodies (MAb) raised against CPV was ...Canine parvovirus (CPV) is a highly contagious pathogen that causes severe disease in dogs and wildlife. Previously, a panel of neutralizing monoclonal antibodies (MAb) raised against CPV was characterized. An antibody fragment (Fab) of MAb E was found to neutralize the virus at low molar ratios. Using recent advances in cryo-electron microscopy (cryo-EM), we determined the structure of CPV in complex with Fab E to 4.1 Å resolution, which allowed de novo building of the Fab structure. The footprint identified was significantly different from the footprint obtained previously from models fitted into lower-resolution maps. Using single-chain variable fragments, we tested antibody residues that control capsid binding. The near-atomic structure also revealed that Fab binding had caused capsid destabilization in regions containing key residues conferring receptor binding and tropism, which suggests a mechanism for efficient virus neutralization by antibody. Furthermore, a general technical approach to solving the structures of small molecules is demonstrated, as binding the Fab to the capsid allowed us to determine the 50-kDa Fab structure by cryo-EM. IMPORTANCE: Using cryo-electron microscopy and new direct electron detector technology, we have solved the 4 Å resolution structure of a Fab molecule bound to a picornavirus capsid. The Fab induced conformational changes in regions of the virus capsid that control receptor binding. The antibody footprint is markedly different from the previous one identified by using a 12 Å structure. This work emphasizes the need for a high-resolution structure to guide mutational analysis and cautions against relying on older low-resolution structures even though they were interpreted with the best methodology available at the time. |
External links | J Virol / PubMed:27535057 / PubMed Central |
Methods | EM (single particle) |
Resolution | 4.1 Å |
Structure data | |
Source |
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Keywords | VIRUS/IMMUNE SYSTEM / parvovirus / antibody / VIRUS-IMMUNE SYSTEM complex |