Identification of a novel ligand binding motif in the transthyretin channel

The design of therapeutic compounds targeting transthyretin (TTR) is challenging due to the low specificity of interaction in the hormone binding site. Such feature is highlighted by the interactions of TTR with diclofenac, a compound with high affinity for TTR, in two dissimilar modes, as evidenced by crystal structure of the complex. We report here structural analysis of the interactions of TTR with two small molecules, 1-amino-5-naphthalene sulfonate (1,5-AmNS) and 1-anilino-8-naphthalene sulfonate (1,8-ANS). Crystal structure of TTR: 1,8-ANS complex reveals a peculiar interaction, through the stacking of the naphthalene ring between the side-chain of Lys15 and Leu17. The sulfonate moiety provides additional interaction with Lys15` and a water-mediated hydrogen bond with Thr119`. The uniqueness of this mode of ligand recognition is corroborated by the crystal structure of TTR in complex with the weak analogue 1,5-AmNS, the binding of which is driven mainly by hydrophobic partition and one electrostatic interaction between the sulfonate group and the Lys15. The ligand binding motif unraveled by 1,8-ANS may open new possibilities to treat TTR amyloid diseases by the elucidation of novel candidates for a more specific pharmacophoric pattern. (C) 2009 Published by Elsevier Ltd.

Conselho Nacional de Desenvolvimento Cientfico e Tecnologico (CNPq)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Millennium Institute for Structural Biology in Biomedicine and Biotechnology

Millennium Institute for Structural Biology in Biomedicine and Biotechnology

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)

Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ)

Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Conselho de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)