2rob | pdb_00002rob

Solution structure of calcium bound soybean calmodulin isoform 4 C-terminal domain

spinqualitylabelsall models 2rob, 20 NMR models Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2rob is a 1 chain structure with sequence from Glycine hispida. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CA Related: 2ro8, 2ro9, 2roa Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The intracellular calcium ion is one of the most important secondary messengers in eukaryotic cells. Ca(2+) signals are translated into physiological responses by EF-hand calcium-binding proteins such as calmodulin (CaM). Multiple CaM isoforms occur in plant cells, whereas only a single CaM protein is found in animals. Soybean CaM isoform 1 (sCaM1) shares 90% amino acid sequence identity with animal CaM (aCaM), whereas sCaM4 is only 78% identical. These two sCaM isoforms have distinct target-enzyme activation properties and physiological functions. sCaM4 is highly expressed during the self-defense reaction of the plant and activates the enzyme nitric-oxide synthase (NOS), whereas sCaM1 is incapable of activating NOS. The mechanism of selective target activation by plant CaM isoforms is poorly understood. We have determined high resolution NMR solution structures of Ca(2+)-sCaM1 and -sCaM4. These were compared with previously determined Ca(2+)-aCaM structures. For the N-lobe of the protein, the solution structures of Ca(2+)-sCaM1, -sCaM4, and -aCaM all closely resemble each other. However, despite the high sequence identity with aCaM, the C-lobe of Ca(2+)-sCaM1 has a more open conformation and consequently a larger hydrophobic target-protein binding pocket than Ca(2+)-aCaM or -sCaM4, the presence of which was further confirmed through biophysical measurements. The single Val-144 --> Met substitution in the C-lobe of Ca(2+)-sCaM1, which restores its ability to activate NOS, alters the structure of the C-lobe to a more closed conformation resembling Ca(2+)-aCaM and -sCaM4. The relationships between the structural differences in the two Ca(2+)-sCaM isoforms and their selective target activation properties are discussed. The solution structures of two soybean calmodulin isoforms provide a structural basis for their selective target activation properties.,Ishida H, Huang H, Yamniuk AP, Takaya Y, Vogel HJ J Biol Chem. 2008 May 23;283(21):14619-28. Epub 2008 Mar 17. PMID:18347016 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Calmodulin

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