Figure 1

Homology model structure predictions of HA monomeric glycoproteins of rgHPAIV and engineered viruses. Protein tertiary structure prediction of engineered HA glycoprotein was performed by homology modelling (see text for details). The crystal structure of 1HA0, with intact loop structure, was used for template generation of predicted homology structure models. (A) Overlay of 1HA0, rgHPAIV and rgLPAIV (1HA0: gold; rgLPAIV: cyan; rgHPAIV: dark teal). Filled black arrowhead indicates 1HA0 and rgLPAIV loops; unfilled arrowhead indicates rgHPAIV loop. 1HA0 template carbohydrate moieties are indicated. (B) Overlay of predicted rgHPAIV and engineered HA monomers; loop structure that contains HACS motif is indicated in box (rgHPAIV, dark teal; rgLPAIV, cyan; M5, light green; M6, dark green; M7, purple; M4, light teal; M8, pink; M9, Red; M2, blue; M1, lilac; M3, dark orange). HA loop structures of mutants M5, M6 and M7 are congruent with the predicted loop structure of rgLPAIV; HA loop structures of M1, M2, M3, M4, M8 and M9 resemble the larger rgHPAIV loop structure, albeit, with variation. (C) Side view of predicted HA loop structures containing the HACS motif. D) Distal view of predicted HA loop structures containing the HACS motif. For (C) and (D) rgLPAIV and rgHPAIV predicted loop structures indicated by filled and unfilled arrowheads, respectively.