Cloning, expression, purification, crystallization and preliminary crystallographic analysis of pseudo death-effector domain of HIPPI, a molecular partner of Huntingtin-interacting protein HIP-1

The formation of a heterodimer between Huntingtin-interacting protein-1 (HIP-­1) and its novel partner HIPPI (HIP-1 protein interactor) through their pseudo death-effector domains (pDEDs) is a key step that recruits caspase-8 and initiates apoptosis. This could be one of the pathways by which apoptosis is increased in Huntington's disease (HD). A construct consisting of the pDED of HIPPI has been cloned and overexpressed as 6NH-tagged protein and purified by Ni-NTA affinity chromatography. Crystals of the pDED of HIPPI were grown in space group P4₁, with unit-cell parameters a = b = 77.42, c = 33.31 Å and a calculated Matthews coefficient of 1.88 Å³ Da^-1 (33% solvent content) with two molecules per asymmetric unit.