Rho transcription factor: Symmetry and binding of bicyclomycin

Citation
F. Vincent et al., Rho transcription factor: Symmetry and binding of bicyclomycin, BIOCHEM, 39(31), 2000, pp. 9077-9083
Citations number
53
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
BIOCHEMISTRY
ISSN journal
0006-2960 → ACNP
Volume
39
Issue
31
Year of publication
2000
Pages
9077 - 9083
Database
ISI
SICI code
0006-2960(20000808)39:31<9077:RTFSAB>2.0.ZU;2-Y
Abstract
The antibiotic bicyclomycin inhibits rho-dependent termination processes by interfering with RNA translocation by preventing RNA binding at the transl ocation site or by uncoupling the translocation process from ATP hydrolysis . Previous studies have shown that bicyclomycin binds near the ATP hydrolys is pocket on rho. The hexameric structure of rho indicates that it is in a class of enzymes with strong sequence similarity to F-1-ATP synthase. The b icyclomycin derivative 5a-formylbicyclomycin, an inhibitor comparable to bi cyclomycin, was previously shown to form a stable imine with rho and when r educed to the amine with NaBH4 to singly label five of the six rho subunits . Lysine-336 was identified by mass spectrometric analysis of trypsin-diges ted fragments as the site of 5a-formylbicyclomycin adduction. A model of rh o was made by threading the rho sequence on the known crystal structure of the alpha and beta subunits of F-1-ATP synthase. The model, along with info rmation concerning the extent and site of 5a-formylbicyclomycin adduction, indicates an overall C6 symmetry for rho subunit organization. We propose t hat the sequence similarity between rho and F-1-ATP synthase extends to a s imilar quaternary structure and an equivalent enzyme mechanism. The propose d mechanism of RNA translocation coupled with ATP hydrolysis changes the ov erall symmetry of rho from C6 to C6/C3.