Open AccessProtein S1 from Escherichia coli Ribosomes: An Improved Isolation Procedure and Shape Determination by Small‐Angle X‐Ray Scattering
Author(s) -
LABISCHINSKI Harald,
SUBRAMANIAN AlapRaman
Publication year - 1979
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1979.tb12973.x
Subject(s) - radius of gyration , scattering , gyration , ribosome , small angle scattering , small angle x ray scattering , escherichia coli , crystallography , radius , chemistry , electron density , x ray , analytical chemistry (journal) , materials science , physics , chromatography , geometry , electron , optics , nuclear magnetic resonance , mathematics , polymer , rna , biochemistry , computer security , quantum mechanics , computer science , gene
Ribosomal protein S1 from Escherichia coli was studied in solution by small‐angle X‐ray scattering and the following parameters were obtained. The radius of gyration R = 8.0 ± 0.2 nm; largest diameter D = 28 nm; molecular weight = (8–9) × 10 4 . The data also yielded (with the assumption of a rigid particle with almost constant electron density) two radii of gyration of cross‐section R q1 = 2.5 ± 0.1 nm and R q2 = 1.05 ± 0.05 nm and molecular volume = 140 nm 3 . The experimental scattering curve of S1 was compared with the theoretical scattering curves for several rigid triaxial homogeneous bodies and the closest fit was given by that of a flat elliptical cylinder with the dimensions of 4.5 nm and 0.88 nm for the two semiaxes and 26.5 nm for height. The results from the present X‐ray scattering studies and those from limited proteolytic digestion of protein S1 [ J. Mol. Biol. 127 , 41–54, (1979)] support the notion that the structure of protein S1 is organized into two distinct subdomains within its elongated overall shape. Protein S1 was purified for this study by an efficient procedure which yielded 12 mg S1/g ribosomes. The isolated protein was fully active in functional tests both before and after X‐ray irradiation.