Using the pure spinor formalism, a particular superstring scattering amplitude involving one closed string and N open string vertex operators in AdS(5) x S-5 is studied. It is shown that the tree-level amplitude containing one supergravity state and N super-Yang-Mills states located on D3-branes near the AdS(5) boundary can be expressed as a d = 4 N = 4 harmonic superspace integral in terms of the supergravity and super-Yang-Mills superfields.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)