Abstract
The structure of the neutral peroxidase from Arabidopsis thaliana (ATP N) has been determined to a resolution of 1.9 A and a free R value of 20.5%. ATP N has the expected characteristic fold of the class III peroxidases, with a C(alpha) r.m.s.d. of 0.82 A when compared with horseradish peroxidase C (HRP C). HRP C is 54% identical to ATP N in sequence. When the structures of four class III plant peroxidases are superimposed, the regions with structural differences are non-randomly distributed; all are located in one half of the molecule. The architecture of the haem pocket of ATP N is very similar to that of HRP C, in agreement with the low small-molecule substrate specificity of all class III peroxidases. The structure of ATP N suggests that the pH dependence of the substrate turnover will differ from that of HRP C owing to differences in polarity of the residues in the substrate-access channel. Since there are fewer hydrogen bonds to haem C17 propionate O atoms in ATP N than in HRP C, it is suggested that ATP N will lose haem more easily than HRP C. Unlike almost all other class III plant peroxidases, ATP N has a free cysteine residue at a similar position to the suggested secondary substrate-binding site in lignin peroxidase.
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Acta Crystallographica. Section D: Biological Crystallography |
| Vol/bind | 56 |
| Udgave nummer | Pt 3 |
| Sider (fra-til) | 372-5 |
| Antal sider | 4 |
| ISSN | 0907-4449 |
| Status | Udgivet - mar. 2000 |