1oiz

From Proteopedia

Revision as of 14:50, 5 November 2007

THE MOLECULAR BASIS OF VITAMIN E RETENTION: STRUCTURE OF HUMAN ALPHA-TOCOPHEROL TRANSFER PROTEIN

Overview

Alpha-tocopherol transfer protein (alpha-TTP) is a liver protein, responsible for the selective retention of alpha-tocopherol from dietary, vitamin E, which is a mixture of alpha, beta, gamma, and delta-tocopherols, and the corresponding tocotrienols. The alpha-TTP-mediated transfer of, alpha-tocopherol into nascent VLDL is the major determinant of plasma, alpha-tocopherol levels in humans. Mutations in the alpha-TTP gene have, been detected in patients suffering from low plasma alpha-tocopherol and, ataxia with isolated vitamin E deficiency (AVED). The crystal structure of, alpha-TTP reveals two conformations. In its closed tocopherol-charged, form, a mobile helical surface segment seals the hydrophobic binding, pocket. In the presence of detergents, an open conformation is observed, which probably represents the membrane-bound form. The selectivity of, alpha-TTP for RRR-alpha-tocopherol is explained from the van der Waals, contacts occurring in the lipid-binding pocket. Mapping the known, mutations leading to AVED onto the crystal structure shows that no, mutations occur directly in the binding pocket.

About this Structure

1OIZ is a Single protein structure of sequence from Homo sapiens with TRT as ligand. Structure known Active Site: AC1. Full crystallographic information is available from OCA.

Reference

The molecular basis of vitamin E retention: structure of human alpha-tocopherol transfer protein., Meier R, Tomizaki T, Schulze-Briese C, Baumann U, Stocker A, J Mol Biol. 2003 Aug 15;331(3):725-34. PMID:12899840

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