This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1oip
From Proteopedia
|
THE MOLECULAR BASIS OF VITAMIN E RETENTION: STRUCTURE OF HUMAN ALPHA-TOCOPHEROL TRANSFER PROTEIN
Contents |
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.
Disease
Known disease associated with this structure: Ataxia with isolated vitamin E deficiency OMIM:[600415]
About this Structure
1OIP is a Single protein structure of sequence from Homo sapiens with and as ligands. Known structural/functional Site: . 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
Page seeded by OCA on Thu Feb 21 14:18:21 2008
Categories: Homo sapiens | Single protein | Baumann, U. | Meier, R. | Schulze-Briese, C. | Stocker, A. | Tomizaki, T. | SO4 | VIV | Ataxia | Aved | Disease mutation | Tocopherol | Transfer protein | Vitamin e transport
