RESUMO
Small-angle x-ray scattering curves from four different species of transfer RNA in solution indicate that the molecules are of very similar size and shape. A model which has regions of the molecule folded tightly around a long helical core gives good agreement with the observed scattering curves.
Assuntos
Conformação de Ácido Nucleico , RNA de Transferência de Metionina/química , RNA de Transferência de Fenilalanina/química , RNA de Transferência de Tirosina/química , Escherichia coli/química , Modelos Moleculares , RNA Bacteriano/química , RNA Fúngico/química , Saccharomyces cerevisiae/química , Difração de Raios XRESUMO
Single-crystal diffraction patterns from Escherichia coli leucine tRNA and yeast formylmethionine tRNA show a tetragonal lattice for the former, with a = 46 angstroms and c = 137 angstroms, and a hexagonal lattice for the latter, with a = 115 angstroms and c = 137 angstroms. Initial analysis suggests a molecule with a long, double helix parallel to the c-axis for both crystals.
Assuntos
Conformação de Ácido Nucleico , RNA de Transferência de Leucina/química , RNA de Transferência de Metionina/química , Cristalografia por Raios X , Escherichia coli/química , Modelos Moleculares , RNA Bacteriano/química , RNA Fúngico/química , Saccharomyces cerevisiae/químicaRESUMO
Reproducible conditions have been developed for crystallization of transfer RNA. The conditions may be applicable to many pure transfer RNA species since identical procedures (except for initial transfer-RNA concentration) yielded good crystals from both yeast and Escherichia coli transfer RNA. These crystals, which must be kept at temperatures below about 10 degrees C and handled in vapor of controlled alcohol concentration, have been studied by x-ray crystallography. The availability of crystals of a nucleic acid opens a route for extending knowledge of the tertiary structure of transfer RNA and its relation to important biological functions.
