Table II.
Results of ES-MS analysis of wild-type and mutant AVR9 peptides
| Peptide | Theoretical Massa | Major Peakb | Difference between Major Peak and Theoretical Massc | Second Peakd | Difference between Second Peak and Theoretical Mass |
|---|---|---|---|---|---|
| D | |||||
| AVR9 (WT)e | 3189.6 | 3188.5 ± 1.4 | 1.1 | ||
| AVR9 (SY)f | 3189.6 | 3189.1 ± 0.1 | 0.5 | ||
| AVR9 (NC)g | 3189.6 | 3391.1 ± 0.7 | 201.5 | ||
| AVR9 (LE)h | 3189.6 | 3390.5 ± 1.7i | 200.9 | 3189.8 ± 0.5i | 0.2 |
| S05A (NC) | 3173.6 | 3171.5 ± 0.3 | 2.1 | ||
| R08K (SY) | 3161.6 | 3160.6 ± 0.1 | 1.0 | ||
| R08K (NC) | 3161.6 | 3364.2 ± 0.1 | 202.6 | 3161.2j | 0.4 |
| F10A (SY) | 3113.5 | 3113.0 ± 0.5 | 0.5 | ||
| F10S (NC) | 3129.5 | 3332.3 ± 0.6 | 202.8 | 3129.3 ± 0.5k | 0.2 |
| R18K (NC) | 3161.6 | 3364.5 ± 0.1 | 202.9 | 3160.6 | 1.0 |
| F21A (SY) | 3113.5 | 3112.6 ± 0.3 | 0.9 | ||
| H22L (NC) | 3165.6 | 3369.6 ± 0.4 | 204.0 | 3165.3 | 0.3 |
| L24S (NC) | 3163.5 | 3367.4 ± 0.4 | 203.9 | ||
| H28L (NC) | 3165.6 | 3368.3 ± 0.6 | 202.7 | 3164.8 | 0.8 |
The molecular mass of the peptide containing three disulfide bonds was calculated.
Mass corresponding to the main peak in the spectrum.
An additional mass of 202 kD can represent the presence of one GlcNAc residue.
Mass corresponding to a second peak detected in some of the spectra. The peak height was generally less than 5% of the main peak.
WT, Wild-type AVR9, isolated from C. fulvum-infected tomato.
SY, Chemically synthesized peptide.
NC, Peptides isolated from PVX::Avr9-infected tobacco.
LE, AVR9 isolated from transgenic tomato.
The two peaks showed similar heights.
Very small additional peaks of 3678 and 3686 D were observed, indicating attachment of larger molecules.
The height of this peak is about one-half that of the height of the main peak.