Fig. 4

Exogenous supplied methoxine is incorporated in vivo and acts as a metabolic analogue of methionine in P. pastoris. Nanobody B was produced under the control of the constitutive Gap promoter in the wild type X-33 strain and in the KM71H strain (Mut^S). Expressions were performed in shake flasks. Methoxine was added to the medium every 8 h (200 mg l⁻¹) over a 48 h period. Relative abundance of the Δ−16 Da variant was done via RP-HPLC analysis followed by total mass measurement using ESI-Q-TOF-MS