{Reference Type}: Journal Article
{Title}: Consensus model of a cyanobacterial light-dependent protochlorophyllide oxidoreductase in its pigment-free apo-form and photoactive ternary complex.
{Author}: Schneidewind J;Krause F;Bocola M;Stadler AM;Davari MD;Schwaneberg U;Jaeger KE;Krauss U;
{Journal}: Commun Biol
{Volume}: 2
{Issue}: 0
{Year}: 2019
{Factor}: 6.548
{DOI}: 10.1038/s42003-019-0590-4
{Abstract}: Photosynthetic organisms employ two different enzymes for the reduction of the C17 = C18 double bond of protochlorophyllide (Pchlide), yielding the chlorophyll precursor chlorophyllide. First, a nitrogenase-like, light-independent (dark-operative) Pchlide oxidoreductase and secondly, a light-dependent Pchlide oxidoreductase (LPOR). For the latter enzyme, despite decades of research, no structural information is available. Here, we use protein structure modelling, molecular dynamics (MD) simulations combined with multi-wavelength analytical ultracentrifugation (MWA-AUC) and small angle X-ray scattering (SAXS) experiments to derive a consensus model of the LPOR apoprotein and the substrate/cofactor/LPOR ternary complex. MWA-AUC and SAXS experiments independently demonstrate that the apoprotein is monomeric, while ternary complex formation induces dimerization. SAXS-guided modelling studies provide a full-length model of the apoprotein and suggest a tentative mode of dimerization for the LPOR ternary complex, supported by published cross-link constraints. Our study provides a first impression of the LPOR structural organization.