Physical and Chemical Studies of the 5'-Domain of the Thermus thermophilus Small Ribosomal Subunit
Peter RYABOKON* and Igor SERDYUK
Group of Nucleoprotein Physics, Institute of Protein Research, Russian Academy of Sciences,Pushchino, Moscow Region, 142292, Russia
Hyperthermophiles are widely used as a source of ribosomes, ribosomal subunits and ribosomal proteins for crystallization. Three-dimentional crystalls of Thermus thermophilus ribosomes and some ribosomal proteins were obtained(1). However three-dimentional high-order structure of the 16S rRNA has not yet been accurately determined.
As an alternative approach we believe it is reasonable to study isolated domains of the ribosomal particles. These ribonucleoprotein (RNP) complexes from hyperthermophile Thermus thermophilus have higher stability and size of these RNP are essentially less than those of the whole ribosome. The 5'-domain of the small ribosomal subunit was prepared by oligo-desoxyribonucleotide-directed cleavage of protein-deficient Thermus thermophilus derivatives of the 30S ribosomal subunit with RNase H. A homogeneous RNP fragment has been isolated as a result of the cleavage and subsequent purification in the sucrose gradient. It correponds to the 5'-domains of the 30S ribosomal subunit (1-530 nt 16S rRNA and S4, S16, S17 ribosomal proteins). Its sedimentation constant (SW20) was about 13S. This RNP-complex may be obtained in sufficient amounts for studying its structure in solution by physical methods.
1. Trakhanov, S.D., Yusupov, M.M., Agalarov, S.C., Garber, M.B., Ryazantsev, S.N., Tishchenko, S.V., and Shirokov,V.A. (1987)FEBS Lett., 220, 319-322.
