Fig. 3
Effect on secretion by substituting proline10 inside inulinase signal sequence. a Western blot assay to examine the level of Est1E-His6 in cell lysate (Cell) and supernatant (Sup). b Comparison of Est1E-His6 in supernatant and cell lysate. c Relative Est1E activity in mutant containing various substitutions of proline10. Activity of Est1E expressed by WT signal sequence is designated as unit 1. Values in (c) and below represent mean ± S.D. from four parallel cultures. Hydrophobicity of residue was represented by ΔG of transfer from phosphatidylcholine interface to water [53]. d Hydrophobicity of residues inside inulinase signal sequence from K. marxianus and K. lactis. The cleavage site of signal peptide (1) and that of pro-insulin (2) are indicated by red arrows. Cleavage sites in K. lactis were predicted by SignalP 4.0 [54]. e Relative activity of Est1E expressed by P10L signal sequence from K. marxianus and K. lactis. Activity of Est1E expressed by WT inulinase signal sequence from K. marxianus is designated as unit 1 (*p < 0.05)