Structural basis of RNA binding discrimination between bacteriophages Qbeta and MS2.
Sequence-specific interactions between RNA stem-loops and coat protein (CP) subunits play vital roles in the life cycles of the RNA bacteriophages, e.g., by allowing translational repression of their replicase cistrons and tagging their own RNA genomes for encapsidation. The CPs of bacteriophages Qbeta and MS2 each discriminate in favor of their cognate translational operators, even in the presence of closely related operators from other phages in vivo. Discrete mutations within the MS2 CP have been shown to relax this discrimination in vitro. We have determined the structures of eight complexes between such mutants and both MS2 and Qbeta stem-loops with X-ray crystallography. In conjunction with previously determined in vivo repression data, the structures enable us to propose the molecular basis for the discrimination mechanism.
Horn
Wilf T
WT
Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.
Tars
Kaspars
K
Grahn
Elin
E
Helgstrand
Charlotte
C
Baron
Andrew J
AJ
Lago
Hugo
H
Adams
Chris J
CJ
Peabody
David S
DS
Phillips
Simon E V
SE
Stonehouse
Nicola J
NJ
Liljas
Lars
L
Stockley
Peter G
PG
D001435:Bacteriophages / Q000737:chemistry / Q000235:genetics*; D001665:Binding Sites; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics; D018360:Crystallography, X-Ray; D019281:Dimerization; D006860:Hydrogen Bonding; D017909:Levivirus / Q000737:chemistry / Q000235:genetics*; D008968:Molecular Conformation; D050505:Mutant Proteins; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011777:Q beta Replicase / Q000737:chemistry / Q000235:genetics*; D012367:RNA, Viral / Q000737:chemistry*; D016601:RNA-Binding Proteins / Q000737:chemistry
D036022:Capsid Proteins; D050505:Mutant Proteins; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D011777:Q beta Replicase