Crystallographic characterization of the PDZ1 domain of the human Na+/H+ exchanger regulatory factor.
The Na(+)/H(+) exchanger regulatory factor (NHERF) contains two PDZ domains that mediate the assembly of transmembrane and cytosolic proteins into functional signal transduction complexes. The human NHERF PDZ1 domain, which spans residues 11-99, interacts specifically with carboxy-terminal residues of the beta2 adrenergic receptor and the cystic fibrosis transmembrane conductance regulator. The NHERF PDZ1 was expressed in Escherichia coli as a soluble protein, purified and crystallized in the unbound form using the vapor-diffusion method with 2 M ammonium sulfate as the precipitant. Diffraction data were collected to 1.5 A resolution using synchrotron radiation. The crystals belong to space group P3(1)21 or P3(2)21, with unit-cell parameters a = b = 51.6, c = 58.9 A, and one molecule in the asymmetric unit.