Open AccessCrystallization of the receptor‐binding domain of parathyroid hormone‐related protein in complex with a neutralizing monoclonal antibody Fab fragment
Author(s) -
McKinstry William J.,
Polekhina Galina,
DiefenbachJagger Hannelore,
Sato Koh,
Onuma Etsuro,
Gillespie Matthew T.,
Martin Thomas J.,
Parker Michael W.
Publication year - 2009
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309109006216
Subject(s) - monoclonal antibody , g protein coupled receptor , receptor , parathyroid hormone , chemistry , molecular replacement , antibody , parathyroid hormone related protein , microbiology and biotechnology , biology , biochemistry , protein structure , calcium , immunology , organic chemistry
Parathyroid hormone‐related protein (PTHrP) plays an important role in regulating embryonic skeletal development and is abnormally regulated in the pathogenesis of skeletal complications observed with many cancers and osteoporosis. It exerts its action through binding to a G‐protein‐coupled seven‐transmembrane cell‐surface receptor (GPCR). Structurally, GPCRs are very difficult to study by X‐ray crystallography. In this study, a monoclonal antibody Fab fragment which recognizes the same region of PTHrP as its receptor, PTH1R, was used to aid in the crystallization of PTHrP. The resultant protein complex was crystallized using the hanging‐drop vapour‐diffusion method with polyethylene glycol as a precipitant. The crystals belonged to the orthorhombic space group P 2 1 2 1 2, with unit‐cell parameters a = 72.6, b = 96.3, c = 88.5 Å, and diffracted to 2.0 Å resolution using synchrotron radiation. The crystal structure will shed light on the nature of the key residues of PTHrP that interact with the antibody and will provide insights into how the antibody is able to discriminate between PTHrP and the related molecule parathyroid homone.