TABLE 3.
Compositions of isobaric forms of sVSG
The measured masses (from Fig. 9) for sVSG221 samples from wild type (WT) and TbUAP conditional null cells grown with (cKO + Tet) or without tetracycline (cKO - Tet) for 48 h are tabulated in that order, followed by (in parentheses) the theoretical mass of the assigned VSG composition (Theo.). NA, not available. The 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.
| Measured (and theoretical) molecular mass of WT/+Tet/−Tet (Theo.) | Proteina | GlcN-Ino-cPb | EtNPb | HexNAc | Hexose | WT | CKO + Tet | CKO − Tet |
|---|---|---|---|---|---|---|---|---|
| Da | ||||||||
| 51,542/51,546/NA (51,531) | 1 | 1 | 1 | 5 | 23 | + | + | − |
| 51,500/51,505/NA (51,490) | 1 | 1 | 1 | 4 | 24 | + | + | − |
| 51,379/51,384/NA (51,369) | 1 | 1 | 1 | 5 | 22 | + | + | − |
| 51,338/51,343/NA (51,328) | 1 | 1 | 1 | 4 | 23 | + | + | − |
| 51,215/51,219/NA (51,207) | 1 | 1 | 1 | 5 | 21 | + | + | − |
| 51,174/51,179/NA (51,166) | 1 | 1 | 1 | 4 | 22 | + | + | − |
| 51,053/51,058/NA (51,045) | 1 | 1 | 1 | 5 | 20 | + | + | − |
| 51,012/51,017/51,016 (51,004) | 1 | 1 | 1 | 4 | 21 | + | + | + |
| 50,891/50,897/50,895 (50,883) | 1 | 1 | 1 | 5 | 19 | + | + | − |
| 50,850/50,856/50,854 (50,842) | 1 | 1 | 1 | 4 | 20 | +++ | +++ | +++ |
| 50,688/50,694/50,691 (50,680) | 1 | 1 | 1 | 4 | 19 | ++ | ++ | ++ |
| 50,526/50,531/50,530 (50,518) | 1 | 1 | 1 | 4 | 18 | + | + | + |
| 50,364/50,369/50,368 (50,356) | 1 | 1 | 1 | 4 | 17 | + | + | + |
| NA/NA/49,311 (49,302) | 1 | 1 | 1 | 2 | 13 | − | − | + |
| NA/NA/49,149 (49,140) | 1 | 1 | 1 | 2 | 12 | − | − | +++ |
| NA/NA/48,987 (48,978) | 1 | 1 | 1 | 2 | 11 | − | − | +++ |
| NA/NA/48,826 (48,816) | 1 | 1 | 1 | 2 | 10 | − | − | + |
| NA/NA/48,663 (48,654) | 1 | 1 | 1 | 2 | 9 | − | − | + |
| NA/NA/48,501 (48,492) | 1 | 1 | 1 | 2 | 8 | − | − | + |
The average molecular weight of sVSG221 polypeptide (46,284 Da) minus amino acids 1-27 (signal peptide) and residues 460-476 (GPI attachment signal sequence) with four disulphide bonds (44).
Components of GPI common to all glycoforms of sVSG221: GlcN-Ino-cP, glucosamine-α1-6-myo-inositol-1,2-cyclic phosphate; EtNP, ethanolamine phosphate.