1X91
Crystal structure of mutant form A of a pectin methylesterase inhibitor from Arabidopsis
Summary for 1X91
| Entry DOI | 10.2210/pdb1x91/pdb |
| Related | 1RJ1 1X8Z 1X90 |
| Descriptor | invertase/pectin methylesterase inhibitor family protein (2 entities in total) |
| Functional Keywords | four-helix bundle, alpha hairpin, disulfide bridge, domain-swapping, linker, proline, mutant, protein binding |
| Biological source | Arabidopsis thaliana (thale cress) |
| Total number of polymer chains | 1 |
| Total formula weight | 16418.69 |
| Authors | Hothorn, M.,Wolf, S.,Aloy, P.,Greiner, S.,Scheffzek, K. (deposition date: 2004-08-19, release date: 2004-12-28, Last modification date: 2024-11-20) |
| Primary citation | Hothorn, M.,Wolf, S.,Aloy, P.,Greiner, S.,Scheffzek, K. Structural insights into the target specificity of plant invertase and pectin methylesterase inhibitory proteins Plant Cell, 16:3437-3447, 2004 Cited by PubMed Abstract: Pectin methylesterase (PME) and invertase are key enzymes in plant carbohydrate metabolism. Inhibitors of both enzymes constitute a sequence family of extracellular proteins. Members of this family are selectively targeted toward either PME or invertase. In a comparative structural approach we have studied how this target specificity is implemented on homologous sequences. By extending crystallographic work on the invertase inhibitor Nt-CIF to a pectin methylesterase inhibitor (PMEI) from Arabidopsis thaliana, we show an alpha-helical hairpin motif to be an independent and mobile structural entity in PMEI. Removal of this hairpin fully inactivates the inhibitor. A chimera composed of the alpha-hairpin of PMEI and the four-helix bundle of Nt-CIF is still active against PME. By contrast, combining the corresponding segment of Nt-CIF with the four-helix bundle of PMEI renders the protein inactive toward either PME or invertase. Our experiments provide insight in how these homologous inhibitors can make differential use of similar structural modules to achieve distinct functions. Integrating our results with previous findings, we present a model for the PME-PMEI complex with important implications. PubMed: 15528298DOI: 10.1105/tpc.104.025684 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.5 Å) |
Structure validation
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