A Unique Human Norovirus Lineage with a Distinct HBGA Binding Interface

RESEARCH ARTICLE A Unique Human Norovirus Lineage with a Distinct HBGA Binding Interface Wu Liu1☯, Yutao Chen2☯, Xi Jiang3,4, Ming Xia3, Yang Yang2, Ming Tan3,4*, Xuemei Li2*, Zihe Rao2 1 School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China, 2 National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, 3 Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio United States of America, 4 University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America ☯ These authors contributed equally to this work. * (MT); (XL) Abstract OPEN ACCESS Citation: Liu W, Chen Y, Jiang X, Xia M, Yang Y, Tan M, et al. (2015) A Unique Human Norovirus Lineage with a Distinct HBGA Binding Interface. PLoS Pathog 11(7): e1005025. doi:10.1371/journal.ppat.1005025 Editor: Jacques Le Pendu, University of Nantes INSERM, U892, FRANCE Received: March 12, 2015 Accepted: June 16, 2015 Published: July 6, 2015 Copyright: © 2015 Liu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: Coordinates and structure factors of the native OIF P protein and the complex with Lea trisaccharide can be found at Accession Numbers of 4RLZ and 4RM0, respectively, in the Protein Data Bank (www.pdb.org). Funding: This work was supported by the National Natural Science Foundation of China (Grant No. 31400639 and 31170702) and the National Basic Research Program (973 Program) (No. 2011CB910304, 2011CB915501, and 2014CBA02003) to ZR and XL. This study was also supported by US National Institute of Health (NIH) (RO1AI089634), the US Agriculture and Food Research Initiative Competitive Grants Program of Norovirus (NoV) causes epidemic acute gastroenteritis in humans, whereby histo-blood group antigens (HBGAs) play an important role in host susceptibility. Each of the two major genogroups (GI and GII) of human NoVs recognizes a unique set of HBGAs through a distinct binding interface that is conserved within a genogroup, indicating a distinct evolutionary path for each genogroup. Here, we characterize a Lewis a (Lea) antigen binding strain (OIF virus) in the GII.21 genotype that does not share the conserved GII binding interface, revealing a new evolution lineage with a distinct HBGA binding interface. Sequence alignment showed that the major residues contributing to the new HBGA binding interface are conserved among most members of the GII.21, as well as a closely related GII.13 genotype. In addition, we found that glycerol inhibits OIF binding to HBGAs, potentially allowing production of cheap antivirals against human NoVs. Taken together, our results reveal a new evolutionary lineage of NoVs selected by HBGAs, a finding that is important for understanding the diversity and widespread nature of NoVs. Author Summary Human norovirus (huNoV) has diverged into two major lineages (GI and GII) selected by the host histo-blood group antigens (HBGAs). Both lineages further diverge into various sub-lineages (genotypes) that recognize different ABH and Lewis antigens through a common HBGA binding interface shared among strains within each genogroup. In this study, through X-ray crystallography of the P domain of a GII.21 huNoV (OIF) we identified a unique lineage in GII consisting of GII.13 and GII.21 genotypes that recognize HBGAs through a binding interface distinct from the GII conventional binding interface. While the mechanism remains unknown, our finding raises an alert on future emergence of new lineages by the same way via developing new receptor binding interfaces, as well as further divergence of this new lineage into more sub-lineages recognizing different HBGAs, which PLOS Pathogens | DOI:10.1371/journal.ppat.1005025 July 6, 2015 1 / 22 A Unique Norovirus Lineage with a Distinct HBGA Binding Interface the USDA NIFA Award (2011-68003-30005), and Cincinnati Children's Hospital Medical Center (T1 and Innovation Fund) to XJ and MT. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript Competing Interests: The authors have declared that no competing interests exist. may impact future epidemiology and strategies for disease control and prevention against huNoVs. Introduction Noroviruses (NoVs) are a group of non-enveloped, single stranded, positive-sense RNA viruses that constitute the Norovirus genus in the family Caliciviridae. NoVs are genetically diverse, containing six genogroups (GI to GVI) with over 35 genetic genotypes. NoVs exhibit wide host tropisms causing diseases in various mammalians including human. Human NoVs (huNoVs), consisting of mainly GI and GII NoVs, are the most important viral cause of epidemic acute gastroenteritis in humans [1], claiming over 200,000 lives each year [2]. NoVs are encapsulated by a protein capsid that is assembled by a single major structural protein, the capsid protein VP1. Each NoV capsid contains 180 copies of VP1, which are organized as a T = 3 icosahedron [3]. VP1 is divided into the N-terminal shell (S) and the C-terminal protruding (P) domain, forming the interior shell and the multiple protrusions of the capsid, respectively [3]. The P domain can be further divided into P1 and P2 subdomains, corresponding to the head as the outermost portion of NoVs, and the leg of the protrusion, respectively. Compared with S and the P1 domain, the P2 domain exhibits the most variable sequences, which are responsible for strain-specific virus-host interactions and immune responses of NoVs. HuNoVs interact with histo-blood group antigens (HBGAs) in a strain-specific manner [4, 5]. HBGAs are fucose-containing glycans in specific sequences as determinants of human and animal blood types, including A/B/O, secretor (H), and Lewis (Le) or non-secretor (H negative) types. They are often present as parts of the carbohydrate moiety of cell surface glycoproteins and glycolipids with N- or O-linkage [6]. The biological roles of HBGAs in huNoV infection have been revealed by human volunteer challenge studies [7–9] and outbreak investigations [10, 11] of huNoVs, in which an association between the host susceptibility and the HBGA binding patterns of huNoVs has been established. Despite the recent breakthroughs in culturing huNoVs in BJAB cells [12], the use of huNoV reverse genetics system [13], and the development of an immunocompromised mouse model [14] for huNoV propagation, an effective cell culture system or an animal model for huNoVs remains lacking. As a result, our understanding on huNoV-HBGA interactions relies mainly on data from in vitro studies using various recombinant subviral particles as models of huNoVs. Virus-like particles (VLPs), which are p (...truncated)