The RNR motif of B. subtilis RNase P protein interacts with both PRNA and pre-tRNA to stabilize an active conformer.
RNA
; 17(7): 1225-35, 2011 Jul.
Article
em En
| MEDLINE
| ID: mdl-21622899
ABSTRACT
Ribonuclease P (RNase P) catalyzes the metal-dependent 5' end maturation of precursor tRNAs (pre-tRNAs). In Bacteria, RNase P is composed of a catalytic RNA (PRNA) and a protein subunit (P protein) necessary for function in vivo. The P protein enhances pre-tRNA affinity, selectivity, and cleavage efficiency, as well as modulates the cation requirement for RNase P function. Bacterial P proteins share little sequence conservation although the protein structures are homologous. Here we combine site-directed mutagenesis, affinity measurements, and single turnover kinetics to demonstrate that two residues (R60 and R62) in the most highly conserved region of the P protein, the RNR motif (R60-R68 in Bacillus subtilis), stabilize PRNA complexes with both P protein (PRNAâ¢P protein) and pre-tRNA (PRNAâ¢P proteinâ¢pre-tRNA). Additionally, these data indicate that the RNR motif enhances a metal-stabilized conformational change in RNase P that accompanies substrate binding and is essential for efficient catalysis. Stabilization of this conformational change contributes to both the decreased metal requirement and the enhanced substrate recognition of the RNase P holoenzyme, illuminating the role of the most highly conserved region of P protein in the RNase P reaction pathway.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Bacillus subtilis
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RNA
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Precursores de RNA
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Ribonuclease P
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Domínios e Motivos de Interação entre Proteínas
Idioma:
En
Revista:
RNA
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Estados Unidos