Ribosome conformational changes associated with protein S6 phosphorylation.

R Kisilevsky,M A Treloar,L Weiler

doi:10.1016/s0021-9258(17)43609-x

Abstract

The relative accessibility of rat liver ribosomal proteins to reductive methylation was examined using ribosomes with unphosphorylated, and extensively phosphorylated S6. Comparison of the results indicated that proteins S3, S4, S7, and S23/24 of the small subunit, and proteins L9, L10, L12, L18, L27, L34, and L36 are involved in a ribosomal conformational change.

Highlights

We have examined the stoichiometryof the methyla- 1 lysine residue is exposed or concealed
Tion reaction and canconclude that we are dealing withwhole The resultswith formaldehyde are similar to thatseen with numbers of lysine residues modified per ribosomal protein, other aldehydespossessinglargersidegroups
(29) or with not fractional changes inlysine residue accessibility to label- lactoperioxidase catalyzed iodination [33],a technique which ing. This conclusion is based on information obtained ina purportedly labels only surface tyrosine groups [34,35,36]

Summary

In the present study the purpose in using unmanipulated

Data Analysis-All data analysiswas performed with a Burroughs animals, and thosgeiven ethionine plus adeninwe,as to induce. The present work compares the conformation of unphoswith the mean :'H/''C ratio, for eachnormalizationcorresponding phorylated ribosomes from unmanipulated animals with that proteins in different treatmentgroups were compared for significant of the most phosphorylated S6 state after treatment with shifts in accessibility to reductive methylation and tables were constructed listingonly comparisons which yielded a p s 0.05. Analysis of the relative accessibility to reductive methylation of corresponding ribosomal proteinsin ribosomes of differing physical state was performed using both the mean "H/"C ratio and the :'H/'''C ratio of individual proteins for malizers" and eliminates this protein from the tables both horizon- normalization. S6 Phosphorylation ated rylated teins in two differing sets of ribosomes were compared for columns of data

DISCUSSION

Small subuni protein

DDD D

DDDD D

The majorbiochemical eventswithinashorttimeafter

Theinhibition of proteinsynthesis is not caused by the