Open AccessEffect of Reconstitution Conditions on the Structure of Escherichia coli 30‐S Ribosomal‐Subunit Components
Author(s) -
LEMIEUX Gerald,
LEFEVRE JeanFrançois,
DAUNE Michel
Publication year - 1974
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1974.tb03824.x
Subject(s) - ribosome , ribosomal protein , ribosomal rna , protein secondary structure , circular dichroism , escherichia coli , stacking , eukaryotic large ribosomal subunit , protein subunit , crystallography , chemistry , 30s , magnesium , hydrogen bond , rna , 50s , biochemistry , molecule , organic chemistry , gene
16‐S RNA and five pure ribosomal proteins (S3, S4, S6, S7 and S8) from Escherichia coli 30‐S subunits were studied by circular dichroism in regard to the reconstitution of biologically active subunits. A small structural variation upon heating could be measured for RNA. It cannot be interpreted in terms of stacking or disruption of hydrogen bonds. However, most proteins underwent important structural modifications when heated to 42°C in reconstitution solvent. This effect was not dependent on the presence of magnesium salt. The relative amounts of secondary structure of native and heat‐denatured ribosomal proteins were calculated by using three reference curves obtained from standard proteins, the exact secondary structure of which has been determined by X‐ray crystallography. In contrast with earlier results, about 18%β‐structure was detected in native proteins. This discrepancy can most probably be attributed to the calculation method used. Results are discussed in relation to reconstitution of ribosomes.