TY  - JOUR
AU  - Panwalkar, Vineet
AU  - Neudecker, Philipp
AU  - Schmitz, Michael
AU  - Lecher, Justin
AU  - Schulte, Marianne
AU  - Medini, Karima
AU  - Stoldt, Matthias
AU  - Brimble, Margaret A
AU  - Willbold, Dieter
AU  - Dingley, Andrew J
TI  - The Nedd4-1 WW Domain Recognizes the PY Motif Peptide through Coupled Folding and Binding Equilibria.
JO  - Biochemistry
VL  - 55
IS  - 4
SN  - 1520-4995
CY  - Columbus, Ohio
PB  - American Chemical Society
M1  - FZJ-2016-01837
SP  - 659 - 674
PY  - 2016
AB  - The four WW domains of human Nedd4-1 (neuronal precursor cell expressed developmentally downregulated gene 4-1) interact with the PPxY (PY) motifs of the human epithelial Na(+) channel (hENaC) subunits, with the third WW domain (WW3*) showing the highest affinity. We have shown previously that the α-hENaC PY motif binding interface of WW3* undergoes conformational exchange on the millisecond time scale, indicating that conformational sampling plays a role in peptide recognition. To further understand this role, the structure and dynamics of hNedd4-1 WW3* were investigated. The nuclear Overhauser effect-derived structure of apo-WW3* resembles the domain in complex with the α-hENaC peptide, although particular side chain conformations change upon peptide binding, which was further investigated by molecular dynamics simulations. Model-free analysis of the (15)N nuclear magnetic resonance spin relaxation data showed that the apo and peptide-bound states of WW3* have similar backbone picosecond to nanosecond time scale dynamics. However, apo-WW3* exhibits pronounced chemical exchange on the millisecond time scale that is quenched upon peptide binding. (1)HN and (15)N Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments at various temperatures revealed that apo-WW3* exists in an equilibrium between the natively folded peptide binding-competent state and a random coil-like denatured state. The thermodynamics of the folding equilibrium was determined by fitting a thermal denaturation profile monitored by circular dichroism spectroscopy in combination with the CPMG data, leading to the conclusion that the unfolded state is populated to ∼20% at 37 °C. These results show that the binding of the hNedd4-1 WW3* domain to α-hENaC is coupled to the folding equilibrium.
LB  - PUB:(DE-HGF)16
C6  - pmid:26685112
UR  - <Go to ISI:>//WOS:000369471800005
DO  - DOI:10.1021/acs.biochem.5b01028
UR  - https://juser.fz-juelich.de/record/283504
ER  -