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Faba-Rodriguez R, Gu Y, Salmon M, Dionisio G, Brinch-Pedersen H, Brearley CA, Hemmings AM. Structure of a cereal purple acid phytase provides new insights to phytate degradation in plants. PLANT COMMUNICATIONS 2022; 3:100305. [PMID: 35529950 PMCID: PMC9073318 DOI: 10.1016/j.xplc.2022.100305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 02/02/2022] [Accepted: 02/17/2022] [Indexed: 06/14/2023]
Abstract
Grain phytate, a mixed metal ion salt of inositol hexakisphosphate, accounts for 60%-80% of stored phosphorus in plants and is a potent antinutrient of non-ruminant animals including humans. Through neofunctionalization of purple acid phytases (PAPhy), some cereals such as wheat and rye have acquired particularly high mature grain phytase activity. As PAPhy activity supplies phosphate, liberates metal ions necessary for seedling emergence, and obviates antinutrient effects of phytate, its manipulation and control are targeted crop traits. Here we show the X-ray crystal structure of the b2 isoform of wheat PAPhy induced during germination. This high-resolution crystal structure suggests a model for phytate recognition that, validated by molecular dynamics simulations, implicates elements of two sequence inserts (termed PAPhy motifs) relative to a canonical metallophosphoesterase (MPE) domain in forming phytate-specific substrate specificity pockets. These motifs are well conserved in PAPhys from monocot cereals, enzymes which are characterized by high specificity for phytate. Tested by mutagenesis, residues His229 in PAPhy motif 4 and Lys410 in the MPE domain, both conserved in PAPhys, are found to strongly influence phytase activity. These results explain the observed phytase activity of cereal PAPhys and open the way to the rational engineering of phytase activity in planta.
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Affiliation(s)
- Raquel Faba-Rodriguez
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Yinghong Gu
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Melissa Salmon
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Giuseppe Dionisio
- Department of Agroecology, Research Center Flakkebjerg, Aarhus University, 4200 Slagelse, Denmark
| | - Henrik Brinch-Pedersen
- Department of Agroecology, Research Center Flakkebjerg, Aarhus University, 4200 Slagelse, Denmark
| | - Charles A. Brearley
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Andrew M. Hemmings
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China
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Oliveira ST, Azevedo MIG, Cunha RMS, Silva CFB, Muniz CR, Monteiro-Júnior JE, Carneiro RF, Nagano CS, Girão MS, Freitas CDT, Grangeiro TB. Structural and functional features of a class VI chitinase from cashew (Anacardium occidentale L.) with antifungal properties. PHYTOCHEMISTRY 2020; 180:112527. [PMID: 33007618 DOI: 10.1016/j.phytochem.2020.112527] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/25/2020] [Accepted: 09/21/2020] [Indexed: 06/11/2023]
Abstract
A partial cDNA sequence from Anacardium occidentale CCP 76 was obtained, encoding a GH19 chitinase (AoChi) belonging to class VI. AoChi exhibits distinct structural features in relation to previously characterized plant GH19 chitinases from classes I, II, IV and VII. For example, a conserved Glu residue at the catalytic center of typical GH19 chitinases, which acts as the proton donor during catalysis, is replaced by a Lys residue in AoChi. To verify if AoChi is a genuine chitinase or is a chitinase-like protein that has lost its ability to degrade chitin and inhibit the growth of fungal pathogens, the recombinant protein was expressed in Pichia pastoris, purified and biochemically characterized. Purified AoChi (45 kDa apparent molecular mass) was able to degrade colloidal chitin, with optimum activity at pH 6.0 and at temperatures from 30 °C to 50 °C. AoChi activity was completely lost when the protein was heated at 70 °C for 1 h or incubated at pH values of 2.0 or 10.0. Several cation ions (Al3+, Cd2+, Ca2+, Pb2+, Cu2+, Fe3+, Mn2+, Rb+, Zn2+ and Hg2+), chelating (EDTA) and reducing agents (DTT, β-mercaptoethanol) and the denaturant SDS, drastically reduced AoChi enzymatic activity. AoChi chitinase activity fitted the classical Michaelis-Menten kinetics, although turnover number and catalytic efficiency were much lower in comparison to typical GH19 plant chitinases. Moreover, AoChi inhibited in vitro the mycelial growth of Lasiodiplodia theobromae, causing several alterations in hyphae morphology. Molecular docking of a chito-oligosaccharide in the substrate-binding cleft of AoChi revealed that the Lys residue (theoretical pKa = 6.01) that replaces the catalytic Glu could act as the proton donor during catalysis.
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Affiliation(s)
- Simone T Oliveira
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil
| | - Mayara I G Azevedo
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil
| | - Rodrigo M S Cunha
- Centro de Ciências Agrárias e Biológicas, Universidade do Vale do Acaraú, Sobral, Ceará, Brazil
| | | | - Celli R Muniz
- Embrapa Agroindústria Tropical, Fortaleza, Ceará, Brazil
| | - José E Monteiro-Júnior
- Laboratório de Genética Molecular, Departamento de Biologia, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil
| | - Rômulo F Carneiro
- Departamento de Engenharia de Pesca, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil
| | - Celso S Nagano
- Departamento de Engenharia de Pesca, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil
| | - Matheus S Girão
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil
| | - Cleverson D T Freitas
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil
| | - Thalles B Grangeiro
- Laboratório de Genética Molecular, Departamento de Biologia, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil.
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Rosenkilde AL, Dionisio G, Holm PB, Brinch-Pedersen H. Production of barley endoprotease B2 in Pichia pastoris and its proteolytic activity against native and recombinant hordeins. PHYTOCHEMISTRY 2014; 97:11-19. [PMID: 24268446 DOI: 10.1016/j.phytochem.2013.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 08/20/2013] [Accepted: 09/02/2013] [Indexed: 06/02/2023]
Abstract
Barley (Hordeum vulgare L.) cysteine proteases are of fundamental biological importance during germination but may also have a large potential as commercial enzyme. Barley cysteine endoprotease B2 (HvEPB2) was expressed in Pichia pastoris from a pPICZαA based construct encoding a HvEPB2 C-terminal truncated version (HvEPB2ΔC) and a proteolytic resistant His6 tag. Maximum yield was obtained after 4 days of induction. Recombinant HvEPB2ΔC (r-HvEPB2ΔC) was purified using a single step of Ni(2+)-affinity chromatography. Purified protein was evaluated by SDS-PAGE, Western blotting and activity assays. A purification yield of 4.26 mg r-HvEPB2ΔC per L supernatant was obtained. r-HvEPB2ΔC follows first order kinetics (Km=12.37 μM) for the substrate Z-Phe-Arg-pNA and the activity was significantly inhibited by the cysteine protease specific inhibitors E64 and leupeptin. The temperature optimum for r-HvEPB2ΔC was 60°C, thermal stability T50 value was 44°C and the pH optimum was 4.5. r-HvEPB2ΔC was incubated with native purified barley seed storage proteins for up to 48 h. After 12h, r-HvEPB2ΔC efficiently reduced the C and D hordeins almost completely, as evaluated by SDS-PAGE. The intensities of the B and γ hordein bands decreased continuously over the 48 h. No degradation occurred in the presence of E64. Recombinant hordeins (B1, B3 and γ1) were expressed in Escherichia coli. After 2h of incubation with r-HvEPB2ΔC, an almost complete degradation of γ1 and partial digests of hordein B1 and B3 were observed.
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Affiliation(s)
- Anne Lind Rosenkilde
- Aarhus University, Faculty of Science and Technology, Dept. of Molecular Biology and Genetics, Research Centre Flakkebjerg, DK-4200 Slagelse, Denmark
| | - Giuseppe Dionisio
- Aarhus University, Faculty of Science and Technology, Dept. of Molecular Biology and Genetics, Research Centre Flakkebjerg, DK-4200 Slagelse, Denmark
| | - Preben B Holm
- Aarhus University, Faculty of Science and Technology, Dept. of Molecular Biology and Genetics, Research Centre Flakkebjerg, DK-4200 Slagelse, Denmark
| | - Henrik Brinch-Pedersen
- Aarhus University, Faculty of Science and Technology, Dept. of Molecular Biology and Genetics, Research Centre Flakkebjerg, DK-4200 Slagelse, Denmark.
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