RT Journal Article SR Electronic(1) A1 Roman-Sosa, Gleyder A1 Karger, Axel A1 Kraatz, Franziska A1 Aebischer, Andrea A1 Wernike, Kerstin A1 Maksimov, Pavlo A1 Lillig, Christopher H. A1 Reimann, Ilona A1 Brocchi, Emiliana A1 Keller, Markus A1 Beer, MartinYR 2017 T1 The amino terminal subdomain of glycoprotein Gc of Schmallenberg virus: disulfide bonding and structural determinants of neutralization JF Journal of General Virology, VO 98 IS 6 SP 1259 OP 1273 DO https://doi.org/10.1099/jgv.0.000810 PB Microbiology Society, SN 1465-2099, AB Orthobunyaviruses are enveloped viruses that can cause human and animal diseases. A novel and major member is the Schmallenberg virus (SBV), the etiological agent of an emerging disease of ruminants that has been spreading all over Europe since 2011. The glycoproteins Gn and Gc of orthobunyaviruses mediate the viral entry, and specifically Gc is a major target for the humoral immune response. For example, the N terminal subdomain of the SBV glycoprotein Gc is targeted by neutralizing monoclonal antibodies that recognize conformational epitopes. Here, we determined the structural features of the N terminus of Gc, and analysed its interaction with monoclonal antibodies. We were able to demonstrate that one of two N-glycosylation sites is essential for secretion and interaction with a subset of Gc-specific monoclonal antibodies. Furthermore, four disulfide bonds (S–S) were identified and the deletion of the third S–S blocked reactivity with another subset of mAbs with virus-neutralizing and non-neutralizing activity. The mutagenesis of the N-glycosylation sites and the disulfide bonds strongly indicated the independent folding of two subdomains within the SBV Gc N terminus. Further, the epitopes recognized by a panel of mAbs could be grouped into two clusters, as revealed by fine mapping using chimeric proteins. Combining the disulfide bonding and epitope mapping allowed us to generate a structural model of the SBV Gc N-terminus. This novel information about the role and structure of the amino terminal region of SBV Gc is of general relevance for the design of antivirals and vaccines against this virus., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/jgv.0.000810