  Recent analyses of backward meson electroproduction support the validity of a
collinear QCD factorization framework for these hard exclusive reactions. This
opens a way to the extraction of nucleon-to-meson transition distribution
amplitudes (TDAs) from the experimental data. Similarly to the generalized
parton distributions, TDAs - after the Fourier transform in the transverse
plane - carry valuable information on the transverse location of hadron
constituents. We address the properties of integrated nucleon-to-meson TDAs in
the impact parameter representation. We argue that the emerging picture
provides an intuitive interpretation for the hadron structural information
contained in nucleon-to-meson TDAs and allows to study diquark-quark contents
of fast moving hadrons in the transverse plane.
