1X90

Crystal structure of mutant form B of a pectin methylesterase inhibitor from Arabidopsis

1X90 の概要

• エントリーDOI: 10.2210/pdb1x90/pdb
• 関連するPDBエントリー: 1X8Z 1X91
• 分子名称: invertase/pectin methylesterase inhibitor family protein (2 entities in total)
• 機能のキーワード: four-helix bundle, alpha hairpin, disulfide bridge, linker, proline, mutant, protein binding
• 由来する生物種: Arabidopsis thaliana (thale cress)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 32607.20

構造登録者

Hothorn, M.,Wolf, S.,Aloy, P.,Greiner, S.,Scheffzek, K. (登録日: 2004-08-19, 公開日: 2004-12-28, 最終更新日: 2024-10-16)

主引用文献

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

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: 15528298
DOI: 10.1105/tpc.104.025684

実験手法

X-RAY DIFFRACTION (2.68 Å)