Open AccessStructural and Functional Studies on Protein S20 from the 30‐S Subunit of the Escherichia coli Ribosome
Author(s) -
PATERAKIS Konstantinos,
LITTLECHILD Jennifer,
WOOLLEY Paul
Publication year - 1983
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1983.tb07083.x
Subject(s) - biochemistry , circular dichroism , ribosome , proteolysis , chemistry , protein subunit , ribosomal protein , 30s , rnase p , tyrosine , protein a/g , biology , rna , enzyme , fusion protein , recombinant dna , gene
Fragments resistant to proteolysis have been obtained from the ribosomal protein S20. They provide evidence for a structural domain stretching from the middle of the protein to its C terminus. With the exception of a large fragment of this protein lacking only 14 residues at the N terminus, all fragments had lost their ability to bind to 16‐S rRNA. The protein in the S20. 16‐S‐RNA complex was highly protected against enzymic digestion, indicating that the entire protein is involved in interaction with the nucleic acid. Circular dichroism showed a high α helix content (36%) for the intact protein and a low α helix content (2%) for the large fragment. Intrinsic fluorescence studies demonstrated that the single tyrosine residue in protein S20 is exposed to the solvent in the intact protein and is not exposed in the S20. 16‐S‐RNA complex. Irreversible thermal denaturation of the protein was followed by fluorescence of the tyrosine and was found between 50°C and 70°C.