1RJ4

Structure of a Cell Wall Invertase Inhibitor from Tobacco in Complex with Cd2+

Summary for 1RJ4

• Entry DOI: 10.2210/pdb1rj4/pdb
• Related: 1RJ1
• Descriptor: invertase inhibitor, CADMIUM ION, 2-[BIS-(2-HYDROXY-ETHYL)-AMINO]-2-HYDROXYMETHYL-PROPANE-1,3-DIOL, ... (4 entities in total)
• Functional Keywords: four-helix bundle, helical hairpin, cadmium coordination, bis-tris buffer, protein binding
• Biological source: Nicotiana tabacum (common tobacco)
• Total number of polymer chains: 4
• Total formula weight: 66090.06

Authors

Hothorn, M.,D'Angelo, I.,Marquez, J.A.,Greiner, S.,Scheffzek, K. (deposition date: 2003-11-18, release date: 2004-02-03, Last modification date: 2024-10-23)

Primary citation

Hothorn, M.,D'Angelo, I.,Marquez, J.A.,Greiner, S.,Scheffzek, K.
The invertase inhibitor Nt-CIF from tobacco: a highly thermostable four-helix bundle with an unusual N-terminal extension
J.Mol.Biol., 335:987-995, 2004

PubMed Abstract: Plant invertases are sucrolytic enzymes essential for plant metabolism and development. Enzyme activity is regulated on a posttranslational level via inhibitory proteins, referred to as invertase inhibitors. Ectopic expression of invertase inhibitors in crop plants has high biotechnological potential. However, little biochemical and up to now no detailed structural information is available about this class of plant regulatory proteins. Here, we present the crystal structure of the cell wall-associated invertase inhibitor Nt-CIF from tobacco at a resolution of 1.87A. The structural model reveals an asymmetric four-helix bundle with an uncommon N-terminal extension that appears to be critical for the structural integrity of the protein. Structure analysis of a second crystal form grown in the presence of CdCl(2) reveals two metal binding sites. Nt-CIF is highly thermostable and retains full inhibitory activity after cooling to ambient temperatures. The structure of Nt-CIF provides the first three-dimensional information source for the posttranslational regulation of plant invertases. Based on the recently discovered sequence homology between inhibitors of invertases and pectin methylesterases, our structural model is likely to represent a scaffold also used for the regulation of the latter enzymes, which do not share sequence similarity with invertases. Thus, our structural model sets the 3D-stage for the investigation of posttranslational regulation of invertases as well as pectin methylesterases.

PubMed: 14698293
DOI: 10.1016/j.jmb.2003.10.066

Experimental method

X-RAY DIFFRACTION (2 Å)