PDBsum entry 1k95

Metal binding protein

PDB id: 1k95

Contents

Protein chain

161 a.a. *

Waters ×132

* Residue conservation analysis

PDB id:

1k95

Name:

Metal binding protein

Title:

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

Structure:

Grancalcin. Chain: a. Fragment: residues 53-217. Synonym: ef-hand calcium-binding protein. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: escherichia coli. Expression_system_taxid: 562

Biol. unit:

Dimer (from PQS)

Resolution:

1.90Å R-factor: 0.211 R-free: 0.259

Authors:

J.Jia,N.Borregaard,K.Lollike,M.Cygler

Key ref:

J.Jia et al. (2001). Structure of Ca(2+)-loaded human grancalcin. Acta Crystallogr D Biol Crystallogr, 57, 1843-1849. PubMed id: 11717497 DOI: 10.1107/S0907444901016511

Date:

26-Oct-01 Release date: 07-Dec-01

Protein chain

P28676  (GRAN_HUMAN) -  Grancalcin from Homo sapiens

Seq: 217 a.a.

Struc: 161 a.a.

DOI no: 10.1107/S0907444901016511

Acta Crystallogr D Biol Crystallogr 57:1843-1849 (2001)

PubMed id: 11717497

Structure of Ca(2+)-loaded human grancalcin.

J.Jia, N.Borregaard, K.Lollike, M.Cygler.

ABSTRACT

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.

Selected figure(s)

Figure 1.
Figure 1 (a) Stereoview of the C^ trace of the des(1-52)grancalcin dimer. The side chains liganding Ca^2+ ions are shown in full. The individual EF-hands are differentiated by color. (b) Cartoon drawing of the dimer. The second monomer is drawn in light blue. Figures prepared with MOLSCRIPT (Kraulis, 1991[Kraulis, P. J. (1991). J. Appl. Cryst. 24, 946-950.]) and RASTER3D (Merritt & Bacon, 1997[Merritt, E. A. & Bacon, D. J. (1997). Methods Enzymol. 277, 505-524.]). (c) Alignment of the sequences of EF1-EF5.

Figure 4.
Figure 4 Superposition of Ca^2+-bound des(1-52)grancalcin and ALG-2. The superposition is based on EF4/5 only. Grancalcin is shown in red, ALG-2 is blue and the ALG-2-bound peptide in cyan.

The above figures are reprinted by permission from the IUCr: Acta Crystallogr D Biol Crystallogr (2001, 57, 1843-1849) copyright 2001.

Figures were selected by an automated process.