Crystallization and preliminary X‐ray diffraction analysis of boar seminal plasma spermadhesin PSP‐I/PSP‐II, a heterodimer of two CUB domains

Abstract

Boar spermadhesin PSP‐I/PSP‐II (M _r 29 000–30 000), a non‐covalent heterodimer of two CUB domains, was crystallized in two crystal forms. Complete diffraction data sets for hexagonal (space group P6_1,522) and trigonal (space group P3_1,221) crystals have been collected up to 2.9 and 2.5 Å resolution, respectively. Cell constants of the hexagonal and trigonal crystal forms are , , and , , respectively. The calculated packing parameters (V _m) are 2.8 and 3.2 ų/Da for the hexagonal and trigonal crystal forms, respectively, indicating that, in both cases, the asymmetric unit is constituted by one PSP‐I/PSP‐II heterodimer. This paper reports the first crystals of a protein built up by a CUB domain architecture.