TY - JOUR

T1 - Assembly of proteins and 5S rRNA to transcripts of the major structural domains of 23S rRNA

AU - Østergaard, P.

AU - Phan, Hien

AU - Johansen, L.B.

AU - Egebjerg, J.

AU - Østergaard, L.

AU - Porse, Bo Torben

AU - Garrett, Roger Antony

N1 - Keywords: Base Sequence; Binding Sites; Escherichia coli; Ions; Models, Molecular; Molecular Sequence Data; Protein Binding; RNA, Bacterial; RNA, Ribosomal, 23S; RNA, Ribosomal, 5S; Ribosomal Proteins; Ribosomes; Temperature

PY - 1998/11/1

Y1 - 1998/11/1

N2 - The six major structural domains of 23 S rRNA from Escherichia coli, and all combinations thereof, were synthesized as separate T7 transcripts and reconstituted with total 50 S subunit proteins. Analysis by one and two-dimensional gel electrophoresis demonstrated the presence of at least one primary binding protein associated with each RNA domain and additional proteins assembled to domains I, II, V and VI. For all the combinations of two to five domains, enhanced assembly yields and/or new proteins were observed primarily to those transcripts containing either domains I+II or domains V+VI. This indicates that there are two major protein assembly centres located at the ends of the 23 S rRNA, which is consistent with an earlier view that in vitro protein assembly nucleates around proteins L24 and L3. Although similar protein assembly patterns were observed over a range of temperature and magnesium concentrations, protein L2 assembled strongly with domains II and IV at 4-8 mM Mg2+ (the first step of the two-step reconstitution procedure) and with domain IV alone at higher Mg2+ concentrations (the second step). It is proposed that this change in protein-RNA binding provides a basis for the two-step reconstitution in vitro. A chemical footprinting approach was employed on the reconstituted protein-domain complexes to localize a putative L4 binding region within domain I to a region that is partially co-structural with the site on the L4-mRNA where L4 binds and inhibits its own translation. A similar approach was used to map the putative binding regions on domain V of protein L9 and the 5 S RNA-L5-L18 complex.

AB - The six major structural domains of 23 S rRNA from Escherichia coli, and all combinations thereof, were synthesized as separate T7 transcripts and reconstituted with total 50 S subunit proteins. Analysis by one and two-dimensional gel electrophoresis demonstrated the presence of at least one primary binding protein associated with each RNA domain and additional proteins assembled to domains I, II, V and VI. For all the combinations of two to five domains, enhanced assembly yields and/or new proteins were observed primarily to those transcripts containing either domains I+II or domains V+VI. This indicates that there are two major protein assembly centres located at the ends of the 23 S rRNA, which is consistent with an earlier view that in vitro protein assembly nucleates around proteins L24 and L3. Although similar protein assembly patterns were observed over a range of temperature and magnesium concentrations, protein L2 assembled strongly with domains II and IV at 4-8 mM Mg2+ (the first step of the two-step reconstitution procedure) and with domain IV alone at higher Mg2+ concentrations (the second step). It is proposed that this change in protein-RNA binding provides a basis for the two-step reconstitution in vitro. A chemical footprinting approach was employed on the reconstituted protein-domain complexes to localize a putative L4 binding region within domain I to a region that is partially co-structural with the site on the L4-mRNA where L4 binds and inhibits its own translation. A similar approach was used to map the putative binding regions on domain V of protein L9 and the 5 S RNA-L5-L18 complex.

U2 - 10.1006/jmbi.1998.2185

DO - 10.1006/jmbi.1998.2185

M3 - Journal article

C2 - 9813114

VL - 284

SP - 227

EP - 240

JO - Journal of Molecular Biology

JF - Journal of Molecular Biology

SN - 0022-2836

IS - 2

ER -