FIG 8.

Intact-protein MS confirms the lack of N. elongata subsp. glycolytica PilE pilin glycosylation. Shown are the in-source fragmentation ESI-MS spectra over a range of 200 to 2,000 m/z and the corresponding deconvoluted molecular mass spectra of intact pilin proteins. The mass at 18,090.5 Da [M + H]⁺ corresponds to the unmodified mature pilin. Na adducts (+22 Da) and K adducts (+38 Da) were detected but are not marked in the spectra. (A) ESI-MS spectrum of purified pilin from a pglC strain (KS945). (B) Deconvoluted molecular mass spectra of intact pilin from the pglC strain. (C) ESI-MS spectrum of purified pilin from a pglH strain (KS1000). (D) Deconvoluted molecular mass spectra of intact pilin from the pglH strain. (E) ESI-MS spectrum of purified pilin from the wild-type strain (KS945). (F) Deconvoluted molecular mass spectra of intact pilin from the wild-type strain.