Identification of NEM-Modified Cysteines in ALV-A Env by Mass Spectrometry

2013-02-21T11:25:32Z (GMT) by Jason G Smith James M Cunningham
<div><p>(A) ALV-A was exposed to PMB or to NHS-Biotin in the presence or absence of sTva. Env was immunoprecipitated with a polyclonal antibody against the C-terminus of TM and biotinylated proteins were detected with streptavidin-HRP. The positions of SU and TM are indicated.</p><p>(B) The purified, deglycosylated SU used for mass spectrometry analysis was quantified by SYPRO Ruby staining. The positions of SU and the PNGase F enzyme used for glycosylation are indicated. Molecular weight standards are in the left lane.</p><p>(C) Mass spectrometry identified three peptides from SU containing NEM-modified cysteine residues (indicated by *).</p><p>(D) Vertical bars represent the cysteines in SU (two of the cysteines are sequential just before position 292) and are positioned to scale. The host range (HR) determinants 1 and 2 are indicated in light grey for reference. The NEM-modified cysteines are numbered.</p></div>