Purification, crystallization and X-ray crystallographic analysis of RPTPH

Abstract

Receptor-type protein tyrosine phosphatases (RPTPs) belong to the protein tyrosine phosphatase (PTP) family and play a critical role in cell signaling. RPTPH, a type of RPTP, consists of long extracellular domains, a transmembrane domain, and a single intracellular domain with phosphatase activity. RPTPH is involved in phosphorylation of target proteins involved in the AKT signaling pathway and regulates T-cell function and cell apoptosis. The protein is also implicated in progression of colorectal and lung cancers. Despite the importance of RPTPH in tumor-related cell signaling and therapeutic drug development, the structure of this enzyme has not yet been determined. We overexpressed, purified, and crystallized the catalytic domain of RPTPH. The RPTPH crystal diffracted at a resolution of 1.56 Å. It belonged to the space group P32 with unit cell parameters a = b = 56.46 Å, c = 80.45 Å, α = β = 90°, and γ = 120°.