  We evaluate the effect of screening by bound electron in the 7Be + p --> 8B +
photon reaction, where 7Be target contains bound electron, in the framework of
the adiabatic representation of the three particle problem. A comparison with
two other approximations (united atom and folding) is presented. A good
agreement between the ``united atom'' approximation and the exact solution is
found. We also discuss the screening corrections induced by two K-shell
electrons on a 7Be target. The bound electron screening effect consequences for
7Be and 8B solar neutrino fluxes are discussed.
