1ZFS

Solution structure of S100A1 bound to calcium

Summary for 1ZFS

• Entry DOI: 10.2210/pdb1zfs/pdb
• Related: 1K2H
• Descriptor: S-100 protein, alpha chain, CALCIUM ION (2 entities in total)
• Functional Keywords: s100, noncovalent homodimer, x-type 4 helix bundle, calcium binding, conformational change, metal binding protein
• Biological source: Rattus norvegicus (Norway rat)
• Cellular location: Cytoplasm: P35467
• Total number of polymer chains: 2
• Total formula weight: 21039.54

Authors

Wright, N.T.,Varney, K.M.,Weber, D.J. (deposition date: 2005-04-20, release date: 2006-04-11, Last modification date: 2024-05-22)

Primary citation

Wright, N.T.,Varney, K.M.,Ellis, K.C.,Markowitz, J.,Gitti, R.K.,Zimmer, D.B.,Weber, D.J.
The three-dimensional solution structure of Ca(2+)-bound S100A1 as determined by NMR spectroscopy
J.Mol.Biol., 353:410-426, 2006

PubMed Abstract: S100A1 is an EF-hand-containing Ca(2+)-binding protein that undergoes a conformational change upon binding calcium as is necessary to interact with protein targets and initiate a biological response. To better understand how calcium influences the structure and function of S100A1, the three-dimensional structure of calcium-bound S100A1 was determined by multidimensional NMR spectroscopy and compared to the previously determined structure of apo. In total, 3354 nuclear Overhauser effect-derived distance constraints, 240 dihedral constraints, 160 hydrogen bond constraints, and 362 residual dipolar coupling restraints derived from a series of two-dimensional, three-dimensional, and four-dimensional NMR experiments were used in its structure determination (>21 constraints per residue). As with other dimeric S100 proteins, S100A1 is a symmetric homodimer with helices 1, 1', 4, and 4' associating into an X-type four-helix bundle at the dimer interface. Within each subunit there are four alpha-helices and a short antiparallel beta-sheet typical of two helix-loop-helix EF-hand calcium-binding domains. The addition of calcium did not change the interhelical angle of helices 1 and 2 in the pseudo EF-hand significantly; however, there was a large reorientation of helix 3 in the typical EF-hand. The large conformational change exposes a hydrophobic cleft, defined by residues in the hinge region, the C terminus, and regions of helix 3, which are important for the interaction between S100A1 and a peptide (TRTK-12) derived from the actin-capping protein CapZ.

PubMed: 16169012
DOI: 10.1016/j.jmb.2005.08.027

Experimental method

SOLUTION NMR