PDBsum entry 1j55

Metal binding protein

PDB id: 1j55

Contents

Protein chain

88 a.a. *

Metals

_CA ×2

Waters ×46

* Residue conservation analysis

PDB id:

1j55

Name:

Metal binding protein

Title:

The crystal structure of ca+-bound human s100p determined at 2.0a resolution by x-ray

Structure:

S-100p protein. Chain: a. Engineered: yes

Source:

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

Biol. unit:

Dimer (from PDB file)

Resolution:

2.00Å R-factor: 0.214 R-free: 0.267

Authors:

H.Zhang,G.Wang,Y.Ding,Z.Wang,R.Barraclough,P.S.Rudland,D.G.Fernig, Z.Rao

Key ref:

H.Zhang et al. (2003). The crystal structure at 2A resolution of the Ca2+ -binding protein S100P. J Mol Biol, 325, 785-794. PubMed id: 12507480 DOI: 10.1016/S0022-2836(02)01278-0

Date:

25-Jan-02 Release date: 07-Jan-03

Protein chain

P25815  (S100P_HUMAN) -  Protein S100-P from Homo sapiens

Seq: 95 a.a.

Struc: 88 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1016/S0022-2836(02)01278-0

J Mol Biol 325:785-794 (2003)

PubMed id: 12507480

The crystal structure at 2A resolution of the Ca2+ -binding protein S100P.

H.Zhang, G.Wang, Y.Ding, Z.Wang, R.Barraclough, P.S.Rudland, D.G.Fernig, Z.Rao.

ABSTRACT

S100P is a small calcium-binding protein of the S100 EF-hand-containing family of proteins. Elevated levels of its mRNA are reported to be associated with the progression to hormone independence and metastasis of prostate cancer and to be associated with loss of senescence in human breast epithelial cells in vitro. The first structure of human recombinant S100P in calcium-bound form is now reported at 2.0A resolution by X-ray diffraction. A flexible linker connects the two EF-hand motifs. The protein exists as a homodimer formed by non-covalent interactions between large hydrophobic areas on monomeric S100P. Experiments with an optical biosensor to study binding parameters of the S100P monomer interaction showed that the association rate constant was faster in the presence of calcium than in their absence, whereas the dissociation rate constant was independent of calcium. The K(d) values were 64(+/-24)nM and 2.5(+/-0.8) microM in the presence and in the absence of calcium ions, respectively. Dimerization of S100P is demonstrated in vivo using the yeast two-hybrid system. The effect of mutation of specific amino acids suggests that dimerization in vivo can be affected by amino acids on the dimer interface and in the hydrophobic core.

Selected figure(s)

Figure 3.
Figure 3. The hydrophobic region of the S100P monomer. (a) A ball- and-stick representation of the hydrophobic core formed by F71, F74, and F15, hydrogen bonds between two b-strands by L28 and V69 are coloured in blue. Phenyl- alanine residues are shown in yellow, and other hydrophobic residues labelled are shown in the same colour as their helices (see Figure 2). The monomer is coloured as in Figure 2. (b) Ribbon and atom sphere surface representations of the hydrophobic globe. The hydro- phobic core is further enlarged to a globe by many hydrophobic residues in khaki. The monomer is coloured in slate-blue, and calcium ions are shown in blue. The atom sphere surface was drawn by the program GRASP. 43

Figure 4.
Figure 4. Ribbon model of the S100P dimer. Two monomers are shown in red and royal blue respectively. Calcium ions are in blue. Amino acid residues 46 --51 are invisible, and are indicated by the broken-line. Regions of contact between the subunits are marked in yellow.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2003, 325, 785-794) copyright 2003.

Figures were selected by an automated process.