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.
| Original language | English |
|---|---|
| Journal | Acta Crystallographica. Section D: Biological Crystallography |
| Volume | 56 |
| Issue number | Pt 3 |
| Pages (from-to) | 372-5 |
| Number of pages | 4 |
| ISSN | 0907-4449 |
| Publication status | Published - Mar 2000 |
Keywords
- Amino Acid Sequence
- Arabidopsis
- Crystallization
- Crystallography, X-Ray
- Escherichia coli
- Models, Molecular
- Molecular Sequence Data
- Peroxidases
- Plant Proteins
- Protein Conformation
- Recombinant Fusion Proteins
- Sequence Alignment
- Sequence Homology, Amino Acid