PR-2 Family Members (ß-1,3-Glucanases) of Tobacco and Other Nicotiana Species
| Class (a) | Member name | Trivial name | Origin (b) | MW (kDa) (c) | pI | Localization |
| I | PR-2e | Glb | Nt (T) | 33 | Basic | Vacuole |
| I | PR-2e | Gla | Nt (S) | 33 | Basic | Vacuole |
| I | PR-2e | Gglb50 | Nt (S) | Basic | Vacuole | |
| I | PR-2e | Gln2 | Nt (S) | Basic | Vacuole | |
| I | Gn2 (d) | Np | Basic | Vacuole | ||
| I | Gn1 (d) | Np | 34 | Basic | Vacuole | |
| I I | PR-2a | PR-2 (I, b4) | Nt | 35 | Acidic | Secreted |
| I I | PR-2b | PR-N (b5), G19 | Nt | 35 | Acidic | Secreted |
| I I | PR-2c | PR-O (b6(b), O') | Nt | 35 | Acidic | Secreted |
| I I | PR-2d | Nt | Acidic | Secreted | ||
| I I | Stylar ßGLU (e) | Sp41a | Nt | 41 | Acidic | Secreted |
| I I | Stylar ßGLU (e) | Sp41b | Nt | 41 | Acidic | Secreted |
| I I I | PR-2d | PR-Q' | Nt | 35 | Acidic | Secreted |
| I V (f) | anther ßGLU (e) | Tag1 | Nt | 35 | Acidic | Secreted |
Table 3.1: © Review
"Functions and Regulation of Plant ß-1,3-Glucanases (PR-2)"
by Leubner-Metzger and Meins (1999).
(a) Classification according to amino acid sequence identity of the mature
proteins.
(b) Nicotiana tabacum (Nt); N. plumbaginifolia (Np); T and
S refer to the N. tometosiformis and N. sylvestris progenitors
of tobacco, respectively.
(c) Approximate molecular weight of mature protein; Selected values from
the literature, which might differ between publications.
(d) Amino acid sequence identity to tobacco ßGLU I enzymes of the
N. plumbaginifolia enzymes is ca. 98 % for Gn2, but only ca. 76
% for Gn1.
(e) Not induced by pathogens, i.e. a "PR-like protein".
(f) Tag1 is assigned to a new class, since it shares only 37-38 % amino
sequence identity to Gla, PR-2, and PR-Q'.
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