TABLE 1.
Masses of E. coli ribosomal proteins determined by MALDI-TOF and electrospray MS
| Protein | Predicted mass (Da) | MALDI-TOF mass (Da) | Difference (Da) | Electrospray mass (Da) | Difference (Da) | Modificationsa |
|---|---|---|---|---|---|---|
| S1 | 61,158.2 | 61,159.0 | +0.8 | |||
| S2 | 26,612.5 | 26,616.9 | +4.4 | 26,623.4 | +10.9 | |
| S3 | 25,852.1 | 25,848.1 | −4.0 | 25,853.2 | +1.1 | |
| S4 | 23,338.0 | 23,335.1 | −2.9 | 23,337.4 | −0.6 | |
| S5 | 17,472.2 | 17,515.0 | +42.8 | 17,514.2 | +42.0 | Acetylated |
| S6 | 15,187.1 | 15,187.3 | +0.2 | C-terminal EE | ||
| S6 | 15,316.2 | 15,314.6 | −1.6 | 15,316.5 | +0.3 | C-terminal EEE |
| S6 | 15,445.3 | 15,444.5 | −0.8 | C-terminal EEEE | ||
| S7 | 19,887.9 | 17,474.1 | −2413.8 | 17,474.1 | −2,413.8 | No residues 156 to 178 |
| S8 | 13,995.4 | 13,994.8 | −0.6 | 13,995.1 | −0.3 | |
| S9 | 14,725.0 | 14,725.7 | +0.7 | 14,725.1 | +0.1 | |
| S10 | 11,735.6 | 11,735.6 | 0.0 | 11,734.6 | −1.0 | |
| S11 | 13,713.8 | 13,728.6 | +14.8 | 13,727.8 | +14.0 | Methylated |
| S12 | 13,605.9 | 13,650.7 | −0.2 | 13,651.9 | +1.0 | β-Methylthiolated |
| S13 | 12,968.2 | 12,967.8 | −0.4 | 12,968.1 | −0.1 | |
| S14 | 11,449.3 | 11,449.2 | −0.1 | 11,449.5 | +0.2 | |
| S15 | 10,137.6 | 10,137.4 | −0.2 | 10,137.5 | −0.1 | |
| S16 | 9,190.6 | 9,190.8 | +0.2 | 9,190.4 | −0.2 | |
| S17 | 9,573.3 | 9,573.7 | +0.4 | 9,573.4 | +0.1 | |
| S18 | 8,855.3 | 8,897.2 | +41.9 | 8,897.8 | +42.5 | Acetylated |
| S19 | 10,299.1 | 10,299.1 | 0.0 | 10,298.9 | −0.2 | |
| S20 | 9,553.2 | 9,554.3 | +1.1 | 9,553.2 | 0.0 | |
| S21 | 8,368.8 | 8,370.5 | +1.7 | 8,368.3 | −0.5 | |
| L1 | 24,598.5 | 24,601.1 | +2.6 | 24,598.4 | −0.1 | |
| L2 | 29,729.3 | 29,729.3 | 0.0 | |||
| L3 | 22,243.6 | 22,260.9 | +17.3 | 22,257.6 | +14.0 | Methylated |
| L4 | 22,086.6 | 22,089.2 | +2.6 | 22,086.7 | +0.1 | |
| L5 | 20,170.4 | 20,170.5 | +0.1 | 20,170.5 | +0.1 | |
| L6 | 18,772.6 | 18,772.4 | −0.2 | 18,773.3 | +0.7 | |
| L7 | 12,164.0 | 12,205.4 | +41.4 | 12,204.6 | +40.6 | Acetylated |
| L9 | 15,769.1 | 15,770.7 | +1.6 | 15,770.0 | +0.9 | |
| L10 | 17,580.4 | 17,583.8 | +3.4 | 17,580.5 | +0.1 | |
| L11 | 14,744.2 | 14,870.8 | +126.6 | 14,869.4 | 125.2 | Methylated 9× |
| L12 | 12,164.0 | 12,164.8 | +0.8 | 12,163.7 | −0.3 | |
| L12 | 12,164.0 | 12,180.8 | +16.8 | 12,176.5 | +12.5 | Methylated |
| L13 | 16,018.6 | 16,018.6 | 0.0 | 16,018.4 | −0.2 | |
| L14 | 13,541.1 | 13,541.6 | +0.5 | 13,541.0 | −0.1 | |
| L15 | 14,980.4 | 14,967.5 | −12.9 | 14,966.6 | −13.8 | |
| L16 | 15,281.2 | 15,325.9 | +44.7 | 15,326.3 | +45.1 | Unknown |
| L17 | 14,364.6 | 14,364.9 | +0.3 | 14,364.6 | 0.0 | |
| L18 | 12,769.6 | 12,769.3 | −0.3 | 12,769.8 | +0.2 | |
| L19 | 13,002.1 | 13,001.9 | −0.2 | 13,002.6 | +0.5 | |
| L20 | 13,365.8 | 13,364.7 | −1.1 | 13,364.7 | −1.1 | |
| L21 | 11,564.4 | 11,564.1 | −0.3 | 11,563.1 | −1.0 | |
| L22 | 12,226.3 | 12,226.5 | +0.2 | 12,226.3 | 0.0 | |
| L23 | 11,199.1 | 11,196.5 | −2.6 | 11,198.8 | −0.3 | |
| L24 | 11,185.0 | 11,185.6 | +0.6 | 11,184.9 | −0.1 | |
| L25 | 10,693.5 | 10,693.4 | −0.1 | 10,693.6 | +0.1 | |
| L26 | 9,553.2 | 9,554.3 | +1.1 | 9,553.2 | 0.0 | |
| L27 | 8,993.3 | 8,993.8 | +0.5 | 8,992.5 | −0.8 | |
| L28 | 8,875.3 | 8,875.4 | +0.1 | 8,875.3 | 0.0 | |
| L29 | 7,273.5 | 7,273.2 | −0.3 | 7,272.9 | +0.4 | |
| L30 | 6,410.6 | 6,410.8 | +0.2 | 6,409.8 | −1.0 | |
| L31 | 7,871.1 | 7,871.0 | −0.1 | 7,870.7 | −0.4 | |
| L32 | 6,315.2 | 6,314.9 | −0.3 | 6,314.6 | −0.6 | |
| L33 | 6,240.4 | 6,255.2 | +14.8 | 6,254.0 | +13.6 | Methylated |
| L34 | 5,380.4 | 5,378.9 | −1.5 | 5,379.9 | −0.5 | |
| L35 | 7,157.8 | 7,159.1 | +1.3 | 7,157.4 | −0.4 | |
| L36 | 4,364.4 | 4,367.3 | −0.9 | 4,363.4 | 0.0 |