Loosening and unfolding ofE. coli50 S ribosomal subunits: Dependence on magnesium content and temperature

✍ Scribed by D. A. Ivanov; M. I. Lerman

• Book ID: 104738407
• Publisher: Springer
• Year: 1976
• Tongue: English
• Weight: 448 KB
• Volume: 3
• Category: Article
• ISSN: 0301-4851
• DOI: 10.1007/bf00357207

✦ Synopsis

Reversible change of 50 S ribosomal subunits to 40 S particles takes place in cold buffered 0.5 M NH4C1 solutions either containing Mg §247 (up to 0.1 M), or free from Mg ~ and even supplemented with EDTA (1 mM). The 40 S particles were stable only within a definite temperature range. Heating of the samples caused completely irreversible unfolding of the 40 S particles. This 'melting' appeared to be co-operative and took place within a very narrow range of temperature, which for samples containing Mg ~ was a linear function of the log of Mg ~ concentration.

The results suggest that two types of bonds maintained the compact structure of the ribosomal subunits: ionic bonds involving Mg ++ and heat-labile weak interactions between ribosomal components. * To whom request on reprints should be addressed.