Fig. 6.

Neuraminidase specificity of HN on the glycan array. In all experiments, a slide incubated with the probe virus at 4°C (untreated array) is compared to a slide incubated with the cleaving virus at 37°C and pH 5 and then the probe virus at 4°C (treated array). (A to C) hPIV1 (A), -2 (B), and -3 (C) bind a treated array at a lower level than an untreated array, indicating destruction of their ligands. Array v. 4.2 was used for panels A and C and v. 3.2 for panel C. (D) Treatment of the array with hPIV1 N does not reduce the binding (i.e., cleave the ligands of) influenza A virus (seasonal H1N1), but treatment with hPIV2 or -3 N does, indicating that hPIV2 and -3 cleave α2-6-linked sialic acids but hPIV1 does not. Array v. 4.1 was used. (E) Motifs found in cleaved structures. For structures corresponding to array glycan numbers, see Table S2 in the supplemental material.