 |
|
Title
|
|
The structure of a protein primer-polymerase complex in the initiation of genome replication.
|
|
|
Authors
|
|
C.Ferrer-Orta,
A.Arias,
R.Agudo,
R.Pérez-Luque,
C.Escarmís,
E.Domingo,
N.Verdaguer.
|
|
|
Ref.
|
|
EMBO J, 2006,
25,
880-888.
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
Picornavirus RNA replication is initiated by the covalent attachment of a UMP
molecule to the hydroxyl group of a tyrosine in the terminal protein VPg. This
reaction is carried out by the viral RNA-dependent RNA polymerase (3D). Here, we
report the X-ray structure of two complexes between foot-and-mouth disease virus
3D, VPg1, the substrate UTP and divalent cations, in the absence and in the
presence of an oligoadenylate of 10 residues. In both complexes, VPg fits the
RNA binding cleft of the polymerase and projects the key residue Tyr3 into the
active site of 3D. This is achieved by multiple interactions with residues of
motif F and helix alpha8 of the fingers domain and helix alpha13 of the thumb
domain of the polymerase. The complex obtained in the presence of the
oligoadenylate showed the product of the VPg uridylylation (VPg-UMP). Two metal
ions and the catalytic aspartic acids of the polymerase active site, together
with the basic residues of motif F, have been identified as participating in the
priming reaction.
|
|
|
|