TABLE 2.
Assignment, observed, and calculated molecular masses of small polypeptides of photosystem II complexes from MALDI-TOF MS of T. elongatus 43H (PsbA1-PSII) and 43H/ΔPsbJ (PsbA1/ΔPsbJ-PSII)
The data correspond to Fig. 3, A and C.
| Identification | MMOBSa | MMCALCb average | MMCALCc monoisotopic | ΔMMd | Number of amino acidse | Putative post-translational modifications | 43H | 43H/ΔPsbJ |
|---|---|---|---|---|---|---|---|---|
| Da | Da | Da | Da | |||||
| ? | 3881.68* | Yes | No | |||||
| PsbT | 3899.49* | 3874.67 | 3872.0968 | +27.39 | 32 (32) | Formylation | Yes | Yes |
| PsbM | 4005.55* | 3980.67 | 3978.1788 | +27.37 | 36 (36) | Formylation | Yes | No |
| 4012.68* | 3980.67 | 3978.1788 | +34.50 | 36 (36) | Acetylation? | Yes | No | |
| PsbJ | 4008.62* | 3973.70 | 3971.1085 | +37.51 | 40 (41) | Acetylation, −Met1 | Yes | No |
| PsbK | 4097.19* | 4099.88 | 4097.3157 | −0.12 | 37 (46) | −Met-1 ∼ Ala-9 | Yes | Yes |
| PsbX | 4184.50* | 4188.02 | 4185.4539 | −0.95 | 40 (50) | −Met-1 ∼ Leu-10 | Yes | Yes |
| PsbL | 4293.83* | 4297.02 | 4294.3220 | −0.49 | 37 (37) | Yes | Yes | |
| PsbI | 4430.26* | 4405.18 | 4402.4163 | +27.84 | 38 (38) | Formylation | Yes | No |
| PsbY | 4609.12* | 4584.61 | 4581.7224 | +27.40 | 41 (43) | Formylation, −Met-1, −Gly-2 | Yes | No |
| PsbF | 4973.74* | 4933.65 | 4930.5996 | +43.14 | 44 (45) | Acetylation, −Met-1 | Yes | No |
| Psb30 | 5061.74* | 5037.15 | 5033.7495 | +27.99 | 46 (46) | Formylation | Yes | Yes |
| PsbZ | 6795.35 | 6764.18 | 6759.8105 | +31.17 | 62 (62) | Formylation | Yes | Yes |
| PsbH | 7223.79 | 7222.49 | 7217.9362 | +1.3 | 65 (66) | −Met-1 | Yes | Yes |
| PsbE | 9441.02 | 9441.53 | 9435.8711 | −0.51 | 83 (84) | −Met-1 | Yes | Yes |
| PsbU | 11643.24 | 11644.81 | 11638.0103 | −1.57 | 104 (134) | −Met-1 ∼ Ala-30 | Yes | No |
| PsbV | 15748.04 | 15130.01 | 15120.8165 | +618.03 | 137 (66) | −Met-1, +haem | Yes | No |
a MMOBS = (peak m/z) − 1, assuming the protein molecules are singly charged. Asterisks correspond to monoisotopic molecular mass.
b Molecular mass calculated average molecular weight.
c Molecular mass calculated from monoisotopic weight.
d ΔMM = MMOBS − MMCALC.
e Number of amino acids is from mature protein, and the number in parentheses indicates the number of amino acids deduced from the open reading sequence.