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1k94

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==Overview==
==Overview==
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Grancalcin is a cytosolic Ca(2+)-binding protein originally identified in, human neutrophils. It belongs to a new class of EF-hand proteins, called, PEF proteins, which contain five EF-hand motifs. At the N-terminus of, grancalcin there is a approximately 50 residue-long segment rich in, glycines and prolines. The fifth EF-hand, unpaired within the monomer, provides a means for dimerization through pairing with its counterpart in, a second molecule. The structure of full-length grancalcin in the apo form, and with one EF3 within the dimer occupied by a Ca(2+) ion have been, determined. Although the N-terminal segment was present in the molecule, this part was disordered in the crystals. Here, the structure of a, truncated form of grancalcin, which is lacking 52 N-terminal residues, in, the presence and absence of Ca(2+) is presented. In the Ca(2+)-bound form, the ions are found in the EF1 and EF3 hands. Binding of Ca(2+) to these, two EF hands produces only minor conformational changes, mostly within the, EF1 Ca(2+)-binding loop. This observation supports the hypothesis, formulated on the basis of the structure of a homologous protein ALG-2, which shows significant differences in the orientation of EF4 and EF5, compared with grancalcin, that calcium is a necessary factor but not, sufficient alone for inducing a significant conformational change in PEF, proteins.
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Grancalcin is a cytosolic Ca(2+)-binding protein originally identified in human neutrophils. It belongs to a new class of EF-hand proteins, called PEF proteins, which contain five EF-hand motifs. At the N-terminus of grancalcin there is a approximately 50 residue-long segment rich in glycines and prolines. The fifth EF-hand, unpaired within the monomer, provides a means for dimerization through pairing with its counterpart in a second molecule. The structure of full-length grancalcin in the apo form and with one EF3 within the dimer occupied by a Ca(2+) ion have been determined. Although the N-terminal segment was present in the molecule, this part was disordered in the crystals. Here, the structure of a truncated form of grancalcin, which is lacking 52 N-terminal residues, in the presence and absence of Ca(2+) is presented. In the Ca(2+)-bound form the ions are found in the EF1 and EF3 hands. Binding of Ca(2+) to these two EF hands produces only minor conformational changes, mostly within the EF1 Ca(2+)-binding loop. This observation supports the hypothesis, formulated on the basis of the structure of a homologous protein ALG-2 which shows significant differences in the orientation of EF4 and EF5 compared with grancalcin, that calcium is a necessary factor but not sufficient alone for inducing a significant conformational change in PEF proteins.
==Disease==
==Disease==
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[[Category: penta-ef-hand protein]]
[[Category: penta-ef-hand protein]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri Feb 15 16:11:57 2008''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:31:26 2008''

Revision as of 11:31, 21 February 2008

Image:1k94.jpg

1k94, resolution 1.70Å

Drag the structure with the mouse to rotate

Crystal structure of des(1-52)grancalcin with bound calcium

Contents

Overview

Grancalcin is a cytosolic Ca(2+)-binding protein originally identified in human neutrophils. It belongs to a new class of EF-hand proteins, called PEF proteins, which contain five EF-hand motifs. At the N-terminus of grancalcin there is a approximately 50 residue-long segment rich in glycines and prolines. The fifth EF-hand, unpaired within the monomer, provides a means for dimerization through pairing with its counterpart in a second molecule. The structure of full-length grancalcin in the apo form and with one EF3 within the dimer occupied by a Ca(2+) ion have been determined. Although the N-terminal segment was present in the molecule, this part was disordered in the crystals. Here, the structure of a truncated form of grancalcin, which is lacking 52 N-terminal residues, in the presence and absence of Ca(2+) is presented. In the Ca(2+)-bound form the ions are found in the EF1 and EF3 hands. Binding of Ca(2+) to these two EF hands produces only minor conformational changes, mostly within the EF1 Ca(2+)-binding loop. This observation supports the hypothesis, formulated on the basis of the structure of a homologous protein ALG-2 which shows significant differences in the orientation of EF4 and EF5 compared with grancalcin, that calcium is a necessary factor but not sufficient alone for inducing a significant conformational change in PEF proteins.

Disease

Known diseases associated with this structure: Cone dystrophy-3 OMIM:[600364], Hemolytic anemia due to gamma-glutamylcysteine synthetase deficiency OMIM:[606857]

About this Structure

1K94 is a Single protein structure of sequence from Homo sapiens with as ligand. Full crystallographic information is available from OCA.

Reference

Structure of Ca(2+)-loaded human grancalcin., Jia J, Borregaard N, Lollike K, Cygler M, Acta Crystallogr D Biol Crystallogr. 2001 Dec;57(Pt 12):1843-9. Epub 2001, Nov 21. PMID:11717497

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