Topography of Ribosomal Proteins: Revised Protein Map of the Small Ribosomal Subunit

A. S. Spirin,^1,2 D. E. Agafonov,¹ V. A. Kolb,¹ and A. Kommer¹

¹Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142292 Russia; fax: (7-095) 924-04-93; E-mail: protres@ipr.serpukhov.su

²To whom correspondence should be addressed.

Submitted July 8, 1996.

Exposure of proteins on the surface of the small (30S) ribosomal subunit of Escherichia coli was studied by the hot tritium bombardment technique (tritium planigraphy). Eight of 21 proteins of the 30S subunit (S3, S8, S10, S12, S15, S16, S17, and S19) had virtually no groups exposed on the surface of the particle, i.e., they were mainly hidden inside. Seven proteins (S1, S4, S5, S7, S18, S20, and S21) were well exposed on the surface of the particle, thus being outside proteins. The remaining proteins (S2, S6, S9, and/or S11, S13, and S14) were partially exposed. On the basis of these results, a revised three-dimensional protein map of the small ribosomal subunit is presented and a corrected model is proposed.

KEY WORDS: ribosome, 30S ribosomal subunit, ribosomal proteins, the hot tritium bombardment technique.

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