Yan Hao, Lockhauserbäumer Julia, Szekeres Gergo Peter, Mallagaray Alvaro, Creutznacher Robert, Taube Stefan, Peters Thomas, Pagel Kevin, Uetrecht Charlotte
Leibniz Institute for Experimental Virology (HPI), 20251 Hamburg, Germany.
Organic Chemistry, Free University Berlin, 14195 Berlin, Germany.
Life (Basel). 2021 Jun 11;11(6):554. doi: 10.3390/life11060554.
Infection by the humannoroviruses (hNoV), for the vast majority of strains, requires attachment of the viral capsid to histo blood group antigens (HBGAs). The HBGA-binding pocket is formed by dimers of the protruding domain (P dimers) of the capsid protein VP1. Several studies have focused on HBGA binding to P dimers, reporting binding affinities and stoichiometries. However, nuclear magnetic resonance spectroscopy (NMR) and native mass spectrometry (MS) analyses yielded incongruent dissociation constants (K) for the binding of HBGAs to P dimers and, in some cases, disagreed on whether glycans bind at all. We hypothesized that glycan clustering during electrospray ionization in native MS critically depends on the physicochemical properties of the protein studied. It follows that the choice of a reference protein is crucial. We analysed carbohydrate clustering using various P dimers and eight non-glycan binding proteins serving as possible references. Data from native and ion mobility MS indicate that the mass fraction of β-sheets has a strong influence on the degree of glycan clustering. Therefore, the determination of specific glycan binding affinities from native MS must be interpreted cautiously.
对于绝大多数毒株而言，人诺如病毒（hNoV）感染需要病毒衣壳附着于组织血型抗原（HBGA）。HBGA结合口袋由衣壳蛋白VP1的突出结构域二聚体（P二聚体）形成。多项研究聚焦于HBGA与P二聚体的结合，报道了结合亲和力和化学计量学。然而，核磁共振波谱法（NMR）和原生质谱法（MS）分析得出的HBGA与P二聚体结合的解离常数（K）不一致，而且在某些情况下，对于聚糖是否结合也存在分歧。我们推测，原生质谱法中电喷雾电离过程中的聚糖聚集严重依赖于所研究蛋白质的物理化学性质。因此，选择参考蛋白至关重要。我们使用各种P二聚体和八种可能作为参考的非聚糖结合蛋白分析了碳水化合物聚集情况。原生质谱法和离子淌度质谱法的数据表明，β折叠的质量分数对聚糖聚集程度有很大影响。因此，从原生质谱法确定特定聚糖结合亲和力时必须谨慎解读。
