TABLE 2.

Isobaric glycoforms of sVSG detected by ES-MS^a

Measured (and theoretical) mass (Da) of WT/uggt KO/WT + dNJ/uggt KO + dNJb	Proteinc	GlcN-Ino-cPd	EtNPd	HexNAc	Hexose	WT	UGGT KO	WT + dNJ	UGGT KO + dNJ
—/—/51,533/— (51,531)	1	1	1	5	23			+
51,494/51,493/51,493/51,499 (51,490)	1	1	1	4	24	+	+	++	+
51,371/51,370/51,368/— (51,369)	1	1	1	5	22	+	+	+
51,329/51,331/51,329/51,324 (51,328)	1	1	1	4	23	+	+	+++	+
51,208/51,209/51,189/51,223 (51,207)	1	1	1	5	21	+	+	+	+
51,168/51,168/51,169/51,155 (51,166)	1	1	1	4	22	+	+	+++	+
51,044/51,044/51,045/51,037 (51,045)	1	1	1	5	20	++	+	+	+
51,005/51,005/51,006/51,002 (51,004)	1	1	1	4	21	++	++	+	+++
50,882/50,882/50,882/50,884 (50,883)	1	1	1	5	19	+	+	+	+
50,842/50,843/50,843/50,840 (50,842)	1	1	1	4	20	+++	+++	+	+++
50,680/50,680/—/50,676 (50,680)	1	1	1	4	19	++	++		++
50,518/50,518/—/50,516 (50,518)	1	1	1	4	18	+	+		+
50,356/50,356/—/50,356 (50,356)	1	1	1	4	17	+	+		+

^aThe abundance of each isobaric group of VSG molecules is indicated as follows: +++, mass peaks >70% of the biggest species; ++, mass peaks >40% of the biggest species; +, mass peaks <40% of the biggest species. WT, wild type.

^bThe measured masses (from Fig. 3) for sVSG221 samples from wild-type cells, TbUGGT null mutant cells (UGGT KO), wild-type cells grown with dNJ (WT + dNJ), and TbUGGT null mutant cells grown with dNJ (UGGT KO + dNJ) are tabulated. The theoretical mass of the assigned VSG composition is shown in parentheses. —, not measured.

^cThe average molecular weight of sVSG221 polypeptide (46,284 Da) minus amino acids 1 to 27 (signal peptide) and residues 460 to 476 (GPI attachment signal sequence) with four disulfide bonds (29).

^dComponents of GPI common to all glycoforms of sVSG221: GlcN-Ino-cP, glucosamine-α1-6-myo-inositol-1,2-cyclic phosphate; EtNP, ethanolamine phosphate.