9LPW
Cryo-EM structure of rice PHS1-DPE1 complex
Summary for 9LPW
| Entry DOI | 10.2210/pdb9lpw/pdb |
| EMDB information | 63277 |
| Descriptor | Alpha-1,4 glucan phosphorylase, 4-alpha-glucanotransferase DPE1, chloroplastic/amyloplastic (2 entities in total) |
| Functional Keywords | complex, starch biosynthersis, rice, maltooligosaccharide elongation, transferase |
| Biological source | Oryza sativa Japonica Group (Japanese rice) More |
| Total number of polymer chains | 4 |
| Total formula weight | 351319.45 |
| Authors | Jian, L.,Junjie, Y. (deposition date: 2025-01-26, release date: 2026-04-22, Last modification date: 2026-07-22) |
| Primary citation | Liu, J.,Wu, X.,He, H.,Yang, X.,Hu, Y.,Zhang, F.,Fan, R.,Wang, X.,Yang, S.,Xiong, L.,Zhang, D.,Yin, P.,Guo, J.,Liu, Z.,Yan, J. The plastidial PHS1-DPE1 complex drives efficient malto-oligosaccharides synthesis in rice starch metabolism. Nat Commun, 17:-, 2026 Cited by PubMed Abstract: Starch serves as a vital energy reserve in plants. During its biosynthesis, malto-oligosaccharides (MOS) are essential primers. One of the key pathways for MOS production involves plastidial α-glucan phosphorylase (PHS1/Pho1) and disproportionating enzyme (DPE1). However, the functional relationship between these enzymes is unclear. Here, we demonstrate that rice PHS1 and DPE1 assemble into a multimeric complex. Cryo-EM structures of the PHS1-DPE1 complex reveal an assembly mechanism and suggest a potential substrate tunnel. Biochemical assays show the complex dramatically enhances catalytic efficiency over individual enzymes. Single-molecule fluorescence resonance energy transfer (smFRET) visualizes conformational dynamics, enabling rapid substrate transfer between the enzymes. We further identify the unique L80 loop in PHS1 as a potential regulator. Its deletion reduces catalytic efficiency and prolongs conformational state lifetimes during substrate transfer, thereby reducing the production of longer MOSs. Our findings establish that the PHS1-DPE1 complex facilitates efficient MOS primer synthesis through efficient substrate transfer or diffusion between the two enzymes, providing mechanistic insight into a critical step of starch biosynthesis with agronomic implications. PubMed: 42069819DOI: 10.1038/s41467-026-72738-5 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (2.78 Å) |
Structure validation
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