PURIFICATION, CRYSTALLIZATION, AND PRELIMINARY-X-RAY CRYSTALLOGRAPHICDATA-ANALYSIS OF SMALL HEAT-SHOCK-PROTEIN HOMOLOG FROM METHANOCOCCUS-JANNASCHII, A HYPERTHERMOPHILE

A gene coding for a small heat shock protein homolog from the hyperthe rmophilic methanogenic Archaeon Methanococcus jannaschii was cloned. T his gene was overexpressed in Escherichia coli harboring rare codon tR NAs and its protein purified and crystallized. Crystals displayed the space group R3 with unit cell dimensions a = b = 171.46 Angstrom and c = 102.13 Angstrom in a hexagonal axis setting. These crystals grew in one week and diffracted to 3.2 Angstrom resolution. The presence of e ight molecules in the asymmetric unit gives a V-m value of 2.2 Angstro m(3)/Da and a solvent content of 44% by volume. The 24-molecule comple x is generated from a subunit by a combination of crystallographic thr eefold symmetry and three types of noncrystallographic symmetries (a t wo-, a three-, and a fourfold). (C) 1998 Academic Press.