Unveiling a drift resistant cryptotope within Marburgvirus nucleoprotein recognized by llama single-domain antibodies

John Anthony Garza, Alexander Bryan Taylor, Laura Jo Sherwood, Peter John Hart, Andrew Hayhurst

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Marburg virus (MARV) is a highly lethal hemorrhagic fever virus that is increasingly re-emerging in Africa, has been imported to both Europe and the US, and is also a Tier 1 bioterror threat. As a negative sense RNA virus, MARV has error prone replication which can yield progeny capable of evading countermeasures. To evaluate this vulnerability, we sought to determine the epitopes of 4 llama single-domain antibodies (sdAbs or VHH) specific for nucleoprotein (NP), each capable of forming MARV monoclonal affinity reagent sandwich assays. Here, we show that all sdAb bound the C-terminal region of NP, which was produced recombinantly to derive X-ray crystal structures of the three best performing antibody-antigen complexes. The common epitope is a trio of alpha helices that form a novel asymmetric basin-like depression that accommodates each sdAb paratope via substantial complementarity-determining region (CDR) restructuring. Shared core contacts were complemented by unique accessory contacts on the sides and overlooks of the basin yielding very different approach routes for each sdAb to bind the antigen. The C-terminal region of MARV NP was unable to be crystallized alone and required engagement with sdAb to form crystals suggesting the antibodies acted as crystallization chaperones. While gross structural homology is apparent between the two most conserved helices of MARV and Ebolavirus, the positions and morphologies of the resulting basins were markedly different. Naturally occurring amino acid variations occurring in bat and human Marburgvirus strains all mapped to surfaces distant from the predicted sdAb contacts suggesting a vital role for the NP interface in virus replication. As an essential internal structural component potentially interfacing with a partner protein it is likely the C-terminal epitope remains hidden or "cryptic" until virion disruption occurs. Conservation of this epitope over 50 years of Marburgvirus evolution should make these sdAb useful foundations for diagnostics and therapeutics resistant to drift.

Original languageEnglish (US)
Article number1234
JournalFrontiers in Immunology
Volume8
Issue numberOCT
DOIs
StatePublished - Oct 2 2017

Fingerprint

Marburgvirus
Single-Domain Antibodies
New World Camelids
Nucleoproteins
Epitopes
Ebolavirus
Antibody Binding Sites
Complementarity Determining Regions
RNA Viruses
Virus Replication
Crystallization
Antigen-Antibody Complex
Virion
Fever
X-Rays
Viruses
Antigens
Amino Acids
Antibodies

Keywords

  • Crystallization chaperone
  • Ebola
  • Filovirus
  • Luciferase
  • Marburg
  • Nucleoprotein
  • sdAb
  • VHH

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

Cite this

Unveiling a drift resistant cryptotope within Marburgvirus nucleoprotein recognized by llama single-domain antibodies. / Garza, John Anthony; Taylor, Alexander Bryan; Sherwood, Laura Jo; Hart, Peter John; Hayhurst, Andrew.

In: Frontiers in Immunology, Vol. 8, No. OCT, 1234, 02.10.2017.

Research output: Contribution to journalArticle

Garza, John Anthony ; Taylor, Alexander Bryan ; Sherwood, Laura Jo ; Hart, Peter John ; Hayhurst, Andrew. / Unveiling a drift resistant cryptotope within Marburgvirus nucleoprotein recognized by llama single-domain antibodies. In: Frontiers in Immunology. 2017 ; Vol. 8, No. OCT.
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