RIBOSOMAL STRUCTURE RESEARCH WITH POLARIZED NEUTRON-SCATTERING

Polarized neutron scattering from dynamically polarized nuclear spin t argets has become a method of macromolecular structure research. The c ontrast created by substitution of the hydrogen isotope H-1 by H-2 is increased by almost a factor of three if polarized neutrons are scatte red by polarized nuclear spins in the sample (spin contrast variation) . Therefore, this method is also suitable to determine small or weakly contrasted labels. Proteins with a mass less than 1 wt% of the backgr ound particle were localized. In this paper, the extended version of p rotein localization is presented: proteins L1, L2, L3, L4 in 50 S and proteins S6, S10 in 70 S. Furthermore, even the position of two weakly contrasted tRNAs bound at the elongating 70 S ribosome were determine d. (C) 1998 Elsevier Science B.V. All rights reserved.