Speaker: Alexander D. Cameron, PhD
Division of Molecular Biosciences, Membrane Protein Crystallography Group, Imperial College, London - UK

HOST

Dr. Manuel Palacín, IRB Barcelona

Friday, 10 September 2010, 12:00h, Aula Fèlix Serratosa

ABSTRACT

Secondary active transporters function by the alternating access model of transport. The basis of this model is that the protein can switch conformation to alternately present the substrate binding site to either side of the membrane. This is well characterized biochemically but due to the difficulties in obtaining the crystal structure of a single transporter in different conformational states, relatively little structural information is known to explain how this process occurs. We have been investigating the sodium-benzyl hydantoin transporter, Mhp1, from Microbacterium liquefaciens. This protein is structurally homologous to a wide variety of transporter proteins that have now been classed as the “LeuT superfamily”. We have solved the structure of the protein in three conformational states. From this we propose a mechanism for switching from the outward-facing open conformation through an occluded structure to the inward-facing open state. The principles of this mechanism are likely to be shared by the other proteins of this superfamily.

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