Characterization of an unusual Rho factor from the high G + C gram-positive bacterium Micrococcus luteus.
J Biol Chem
; 271(2): 742-7, 1996 Jan 12.
Article
en En
| MEDLINE
| ID: mdl-8557681
A transcription termination factor (Rho) was purified from the Gram-positive bacterium Micrococcus luteus, and the complete gene sequence was determined. The M. luteus Rho polypeptide has 690 residues, which is 271 residues more than its homolog from Escherichia coli. Most of the additional residues compose a highly charged, hydrophilic segment that is inserted in a non-conserved region between two conserved regions of the RNA-binding domain of the known Rho homolog proteins. This segment extends from residues 49 to 311 and includes a stretch of 238 residues that contain no hydrophobic side chains. Biochemical studies indicate that the M. luteus protein is very similar to E. coli Rho in terms of its RNA-dependent NTPase activity and its sensitivity to the Rho-specific inhibitor bicyclomycin. However, the M. luteus protein has a less stringent RNA cofactor specificity. It also acts to terminate RNA transcription with E. coli RNA polymerase on the lambda cro DNA template, but at much earlier termination stop points than those recognized by E. coli Rho. Thus, the M. luteus protein functions as a true Rho factor, but with a different specificity than that of E. coli Rho. We propose that this altered specificity is consistent with its need to function on transcripts that have a high content of G + C residues.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Factor Rho
/
Micrococcus luteus
Idioma:
En
Revista:
J Biol Chem
Año:
1996
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos