Abstract: Equine arteritis virus (EAV) is a positive-stranded RNA virus of the Arteriviridae family. Its GP5/M dimer, the principal component of the viral envelope, mediates virus budding and serves as a key target for neutralizing antibodies. Using AlphaFold3, we predicted the 3D structure of the EAV GP5/M dimer and compared it to its homolog in porcine reproductive and respiratory syndrome virus (PRRSV). Both complexes share a conserved architecture comprising a short ectodomain, three helical transmembrane regions, and a β-sheet-rich endodomain. EAV GP5 features a longer ectodomain with four α-helices and a disulfide-linked β-sheet, which forms the most variable and surface-exposed region containing neutralizing epitopes. Adjacent conserved and variable N-glycosylation sites suggest immune evasion mechanisms involving antigenic drift and glycan shielding. Another epitope, located in a membrane-proximal helix, overlaps with known virulence and persistence determinants. The transmembrane domains are the most structurally conserved regions between EAV and PRRSV, characterized by tilted and kinked helices stabilized by hydrophilic interactions within the lipid bilayer. These findings provide molecular insights into the structural organization, immune targets, and virulence-associated features of the GP5/M dimer, offering a foundation for rational vaccine design against EAV.
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Overview
This research focuses on computationally predicting the 3D structure of the equine arteritis virus (EAV) GP5/M dimer using AlphaFold3.
The study compares this structure to a similar protein in a related virus, revealing insights into immune evasion, virus structure, and virulence.
Background and Significance
Equine arteritis virus (EAV): A positive-stranded RNA virus within the Arteriviridae family that infects horses and causes respiratory and reproductive disease.
GP5/M dimer: The main protein complex embedded in the viral envelope, responsible for virus budding from the host cell and serving as a primary target for the host’s neutralizing antibodies.
Understanding the structure of GP5/M can reveal how the virus interacts with the host immune system and how it maintains virulence.
Methodology
Structural prediction: Utilized AlphaFold3, an advanced machine-learning tool for protein folding, to predict the 3D structure of the EAV GP5/M dimer.
Comparative analysis: Compared the EAV GP5/M structure with its homologous complex from porcine reproductive and respiratory syndrome virus (PRRSV), another arterivirus with similar structural features.
Key Structural Features Identified
General architecture: Both EAV and PRRSV GP5/M dimers share a conserved overall structure including:
A short ectodomain (portion of protein outside the viral membrane)
Three helical transmembrane regions (spanning the viral membrane)
A β-sheet-rich endodomain (portion inside the viral membrane or cytoplasmic side)
Ectodomain of EAV GP5:
Longer than that in PRRSV
Contains four α-helices and a disulfide-linked β-sheet structure
Forms the most variable and surface-exposed region, which harbors neutralizing antibody epitopes
N-glycosylation sites:
Conserved and variable sites are located adjacent to the neutralizing epitopes
These glycans likely contribute to immune evasion via:
Antigenic drift – the accumulation of mutations to escape antibody recognition
Overlaps with regions known to influence viral virulence and persistence in the host
Transmembrane domain conservation:
Most structurally conserved part between EAV and PRRSV
Consists of tilted and kinked α-helices
Stabilized by hydrophilic interactions within the lipid bilayer, maintaining protein integrity
Biological and Clinical Implications
Immune evasion: The arrangement of glycosylation sites and variable ectodomain structures suggest mechanisms by which EAV avoids detection by host antibodies.
Virulence factors: Specific structural epitopes correspond to viral features that modulate how aggressively EAV infects and persists in its host.
Vaccine design potential:
Knowing the detailed 3D structure of the GP5/M dimer provides a blueprint for designing vaccines that target conserved and vulnerable viral regions.
Insights into glycan shielding and epitope variation can guide strategies to produce broadly neutralizing vaccine candidates.
Conclusion
The research delivers a high-resolution structural model of the EAV GP5/M dimer, highlighting its key functional and immunological features.
These findings offer foundational knowledge useful for understanding virus-host interactions and steering future efforts in antiviral therapies and vaccine development against EAV.
Cite This Article
APA
Veit M, Matczuk AK.
(2026).
Computational modelling of the equine arteritis virus GP5/M Dimer: Implications for immune evasion and virulence.
PLoS One, 21(3), e0344287.
https://doi.org/10.1371/journal.pone.0344287
Institut für Virologie, Veterinärmedizin, Freie Universität Berlin, Berlin, Germany.
Matczuk, Anna Karolina
Division of Microbiology, Department of Pathology, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Wrocław, Poland.
MeSH Terms
Equartevirus / pathogenicity
Equartevirus / immunology
Equartevirus / chemistry
Immune Evasion
Viral Envelope Proteins / chemistry
Viral Envelope Proteins / immunology
Protein Multimerization
Animals
Models, Molecular
Virulence
Horses
Amino Acid Sequence
Computer Simulation
Porcine respiratory and reproductive syndrome virus / immunology
Porcine respiratory and reproductive syndrome virus / chemistry
Epitopes / immunology
Epitopes / chemistry
Conflict of Interest Statement
The authors have declared that no competing interests exist.
References
This article includes 73 references
Balasuriya UBR. Equine viral arteritis. Vet Clin North Am Equine Pract 2014;30(3):543–60.
Bailey AL, Lauck M, Weiler A, Sibley SD, Dinis JM, Bergman Z. High genetic diversity and adaptive potential of two simian hemorrhagic fever viruses in a wild primate population. PLoS One 2014;9(3):e90714.
Lauck M, Hyeroba D, Tumukunde A, Weny G, Lank SM, Chapman CA. Novel, divergent simian hemorrhagic fever viruses in a wild Ugandan red colobus monkey discovered using direct pyrosequencing. PLoS One 2011;6(4):e19056.
Kuhn JH, Lauck M, Bailey AL, Shchetinin AM, Vishnevskaya TV, Bào Y. Reorganization and expansion of the nidoviral family Arteriviridae. Arch Virol 2016;161(3):755–68.
Warren CJ, Yu S, Peters DK, Barbachano-Guerrero A, Yang Q, Burris BL. Primate hemorrhagic fever-causing arteriviruses are poised for spillover to humans. Cell 2022;185(21):3980-3991.e18.
Veit M, Matczuk AK, Sinhadri BC, Krause E, Thaa B. Membrane proteins of arterivirus particles: structure, topology, processing and function. Virus Res 2014;194:16–36.
Wieringa R, de Vries AAF, van der Meulen J, Godeke G-J, Onderwater JJM, van Tol H. Structural protein requirements in equine arteritis virus assembly. J Virol 2004;78(23):13019–27.
Wissink EHJ, Kroese MV, van Wijk HAR, Rijsewijk FAM, Meulenberg JJM, Rottier PJM. Envelope protein requirements for the assembly of infectious virions of porcine reproductive and respiratory syndrome virus. J Virol 2005;79(19):12495–506.
Tian D, Wei Z, Zevenhoven-Dobbe JC, Liu R, Tong G, Snijder EJ. Arterivirus minor envelope proteins are a major determinant of viral tropism in cell culture. J Virol 2012;86(7):3701–12.
Verheije MH, Welting TJM, Jansen HT, Rottier PJM, Meulenberg JJM. Chimeric arteriviruses generated by swapping of the M protein ectodomain rule out a role of this domain in viral targeting. Virology 2002;303(2):364–73.
Shaw TM, Huey D, Mousa-Makky M, Compaleo J, Nennig K, Shah AP. The neonatal Fc receptor (FcRn) is a pan-arterivirus receptor. Nat Commun 2024;15(1):6726.
Yang K, Dong J, Li J, Zhou R, Jia X, Sun Z. The neonatal Fc receptor (FcRn) is required for porcine reproductive and respiratory syndrome virus uncoating. J Virol 2025;99(1):e0121824.
Das PB, Dinh PX, Ansari IH, de Lima M, Osorio FA, Pattnaik AK. The minor envelope glycoproteins GP2a and GP4 of porcine reproductive and respiratory syndrome virus interact with the receptor CD163. J Virol 2010;84(4):1731–40.
de Vries AA, Post SM, Raamsman MJ, Horzinek MC, Rottier PJ. The two major envelope proteins of equine arteritis virus associate into disulfide-linked heterodimers. J Virol 1995;69(8):4668–74.
Thaa B, Kaufer S, Neumann SA, Peibst B, Nauwynck H, Krause E. The complex co-translational processing of glycoprotein GP5 of type 1 porcine reproductive and respiratory syndrome virus. Virus Res 2017;240:112–20.
Thaa B, Sinhadri BC, Tielesch C, Krause E, Veit M. Signal peptide cleavage from GP5 of PRRSV: a minor fraction of molecules retains the decoy epitope, a presumed molecular cause for viral persistence. PLoS One 2013;8(6):e65548.
Veit M, Gadalla MR, Zhang M. Using Alphafold2 to Predict the Structure of the Gp5/M Dimer of Porcine Respiratory and Reproductive Syndrome Virus. Int J Mol Sci 2022;23(21).
Snijder EJ, Dobbe JC, Spaan WJM. Heterodimerization of the two major envelope proteins is essential for arterivirus infectivity. J Virol 2003;77(1):97–104.
Zhang M, Han X, Osterrieder K, Veit M. Palmitoylation of the envelope membrane proteins GP5 and M of porcine reproductive and respiratory syndrome virus is essential for virus growth. PLoS Pathog 2021;17(4):e1009554.
Balasuriya UB, Patton JF, Rossitto PV, Timoney PJ, McCollum WH, MacLachlan NJ. Neutralization determinants of laboratory strains and field isolates of equine arteritis virus: identification of four neutralization sites in the amino-terminal ectodomain of the G(L) envelope glycoprotein. Virology 1997;232(1):114–28.
Fiers J, Cay AB, Maes D, Tignon M. A Comprehensive Review on Porcine Reproductive and Respiratory Syndrome Virus with Emphasis on Immunity. Vaccines (Basel) 2024;12(8):942.
Jumper J, Evans R, Pritzel A, Green T, Figurnov M, Ronneberger O. Highly accurate protein structure prediction with AlphaFold. Nature 2021;596(7873):583–9.
Abramson J, Adler J, Dunger J, Evans R, Green T, Pritzel A. Accurate structure prediction of biomolecular interactions with AlphaFold 3. Nature 2024;630(8016):493–500.
Wrapp D, Wang N, Corbett KS, Goldsmith JA, Hsieh C-L, Abiona O. Cryo-EM structure of the 2019-nCoV spike in the prefusion conformation. Science 2020;367(6483):1260–3.
Ostrowski M, Galeota JA, Jar AM, Platt KB, Osorio FA, Lopez OJ. Identification of neutralizing and nonneutralizing epitopes in the porcine reproductive and respiratory syndrome virus GP5 ectodomain. J Virol 2002;76(9):4241–50.
Liaci AM, Steigenberger B, Telles de Souza PC, Tamara S, Gröllers-Mulderij M, Ogrissek P. Structure of the human signal peptidase complex reveals the determinants for signal peptide cleavage. Mol Cell 2021;81(19):3934-3948.e11.
Matczuk AK, Kunec D, Veit M. Co-translational processing of glycoprotein 3 from equine arteritis virus: N-glycosylation adjacent to the signal peptide prevents cleavage. J Biol Chem 2013;288(49):35396–405.
Firth AE, Zevenhoven-Dobbe JC, Wills NM, Go YY, Balasuriya UBR, Atkins JF. Discovery of a small arterivirus gene that overlaps the GP5 coding sequence and is important for virus production. J Gen Virol 2011;92(Pt 5):1097–106.
Johnson CR, Griggs TF, Gnanandarajah J, Murtaugh MP. Novel structural protein in porcine reproductive and respiratory syndrome virus encoded by an alternative ORF5 present in all arteriviruses. J Gen Virol 2011;92(Pt 5):1107–16.
Li D, Zhu L, Cui C, Wu Z, Qing P, Zhou Q. The role of major and minor structural proteins of porcine reproductive and respiratory syndrome virus in induction of protective immunity. Front Microbiol 2025;16:1563186.
Zhang Z, Nomura N, Muramoto Y, Ekimoto T, Uemura T, Liu K. Structure of SARS-CoV-2 membrane protein essential for virus assembly. Nat Commun 2022;13(1):4399.
Dutta M, Dolan KA, Amiar S, Bass EJ, Sultana R, Voth GA. Direct lipid interactions control SARS-CoV-2 M protein conformational dynamics and virus assembly. bioRxiv 2024.
Laporte M, Jochmans D, Bardiot D, Desmarets L, Debski-Antoniak OJ, Mizzon G. A coronavirus assembly inhibitor that targets the viral membrane protein. Nature 2025;640(8058):514–23.
Van Damme E, Abeywickrema P, Yin Y, Xie J, Jacobs S, Mann MK. A small-molecule SARS-CoV-2 inhibitor targeting the membrane protein. Nature 2025;640(8058):506–13.
Miller AN, Houlihan PR, Matamala E, Cabezas-Bratesco D, Lee GY, Cristofori-Armstrong B. The SARS-CoV-2 accessory protein Orf3a is not an ion channel, but does interact with trafficking proteins.. Elife 2023;12:e84477.
Mirdita M, Schütze K, Moriwaki Y, Heo L, Ovchinnikov S, Steinegger M. ColabFold: making protein folding accessible to all.. Nat Methods 2022;19(6):679–82.
Lomize MA, Pogozheva ID, Joo H, Mosberg HI, Lomize AL. OPM database and PPM web server: resources for positioning of proteins in membranes.. Nucleic Acids Res 2012;40(Database issue):D370-6.
Yariv B, Yariv E, Kessel A, Masrati G, Chorin AB, Martz E. Using evolutionary data to make sense of macromolecules with a “face-lifted” ConSurf.. Protein Sci 2023;32(3):e4582.