Assembly of the 30S subunit from Escherichia coli ribosomes occurs via two assembly domains which are initiated by S4 and S7

Journal Article · Tue Sep 06 04:00:00 EDT 1988 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00418a057· OSTI ID:6470260

Nowotny, V; Nierhaus, K H

A protein which initiates assembly of ribosomes is defined as a protein which binds to the respective rRNA without cooperativity (i.e., without the help of other proteins) during the onset of assembly and is essential for the formation of active ribosomal subunits. The number of proteins binding without cooperativity was determined by monitoring the reconstitution output of active particles at various inputs of 16S rRNA, in the present of constant amounts of 30S-derived proteins (TP30): This showed that only two of the proteins of the 30S subunit are assembly-initiator proteins. These two proteins are still present on a LiCl core particle comprising 16S rRNA and 12 proteins (including minor proteins). The 12 proteins were isolated, and a series of reconstitution experiments at various levels of rRNA excess demonstrated that S4 and S7 are the initiator proteins. Pulse-chase experiments performed during the early assembly with /sup 14/C- and /sup 3/H-labeled TP30 and the determination of the /sup 14/C//sup 3/H ratio of the individual proteins within the assembled particles revealed a bilobal structure of the 30S assembly: A group of six proteins headed by S4 (namely, S4, S20, S16, S15, S6, and S18) resisted the chasing most efficiently (S4 assembly domain). None of the proteins depending on S7 during assembly were found in this group but rather in a second group with intermediate chasing stability (S7 assembly domain; consisting of S7, S9, (S8), S19, and S3). A number of proteins could be fully chased during the early assembly and therefore represent late assembly proteins (S10, S5, S13, S2, S21, S1). These findings fit well with the 30S assembly map. These data, together with the assembly map, imply that S8 and S5 play an important role in the interconnection of the two assembly domains.

• Research Organization: Max-Planck Institut fuer Molekulare Genetik, Berlin-Dahlem (Germany, F.R.)
• OSTI ID: 6470260
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 27:18; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
BACTERIA
CARBON 14 COMPOUNDS
CELL CONSTITUENTS
ESCHERICHIA COLI
ISOTOPE RATIO
LABELLED COMPOUNDS
MICROORGANISMS
MOLECULAR STRUCTURE
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
PROTEINS
RIBOSOMAL RNA
RIBOSOMES
RNA
TRITIUM COMPOUNDS