INVESTIGADORES
DE PRAT GAY Gonzalo
artículos
Título:
Modular unfolding and dissociation of the human respiratory syncytial virus phosphoprotein p and its interaction with the m(2-1) antiterminator: a singular tetramer-tetramer interface arrangement.
Autor/es:
ESPERANTE, S.A.; PARIS, G.; PRAT GAY, G. DE
Revista:
BIOCHEMISTRY
Editorial:
AMER CHEMICAL SOC
Referencias:
Lugar: Washington; Año: 2012 vol. 51 p. 8100 - 8110
ISSN:
0006-2960
Resumen:
Paramyxoviruses share the essential RNA polymerase complex components,
namely, the polymerase (L), phosphoprotein (P), and nucleoprotein (N).
Human respiratory syncytial virus (RSV) P is the smallest polypeptide
among the family, sharing a coiled coil tetramerization domain, which
disruption renders the virus inactive. We show that unfolding of P
displays a first transition with low cooperativity but substantial loss
of α-helix content and accessibility to hydrophobic sites, indicative of
loose chain packing and fluctuating tertiary structure, typical of
molten globules. The lack of unfolding baseline indicates a native state
in conformational exchange and metastable at 20 °C. The second
transition starts from a true intermediate state, with only the
tetramerization domain remaining folded. The tetramerization domain
undergoes a two-state dissociation/unfolding reaction (37.3 kcal
mol(-1)). The M(2-1) transcription antiterminator, unique to RSV and
Metapneumovirus, forms a nonglobular P:M(2-1) complex with a 1:1
stoichiometry and a K(D) of 8.1 nM determined by fluorescence
anisotropy, far from the strikingly coincident dissociation range of P
and M(2-1) tetramers (10(-28) M(3)). The M(2-1) binding region has been
previously mapped to the N-terminal module of P, strongly suggesting the
latter as the metastable molten globule domain. Folding,
oligomerization, and assembly events between proteins and with RNA are
coupled in the RNA polymerase complex. Quantitative assessment of the
hierarchy of these interactions and their mechanisms contribute to the
general understanding of RNA replication and transcription in
Paramyxoviruses. In particular, the unique P-M(2-1) interface present in
RSV provides a valuable antiviral target for this worldwide spread
human pathogen