| Structural highlights
1r5l is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: |
| | NonStd Res: | |
| Gene: | TTPA OR TPP1 (Homo sapiens) |
| Resources: | FirstGlance, OCA, RCSB, PDBsum |
Disease
[TTPA_HUMAN] Defects in TTPA are the cause of ataxia with isolated vitamin E deficiency (AVED) [MIM:277460]. AVED is an autosomal recessive disease characterized by spinocerebellar degeneration. It causes ataxia and peripheral neuropathy that resembles Friedreich ataxia. AVED patients have markedly reduced plasma levels of vitamin E.[1] [2] [3] [4] [5] [6]
Function
[TTPA_HUMAN] Binds alpha-tocopherol and enhances its transfer between separate membranes.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Human alpha-tocopherol (alpha-T) transfer protein (ATTP) plays a central role in vitamin E homeostasis, preventing degradation of alpha-T by routing this lipophilic molecule for secretion by hepatocytes. Mutations in the gene encoding ATTP have been shown to cause a severe deficiency in alpha-T, which results in a progressive neurodegenerative spinocerebellar ataxia, known as ataxia with vitamin E deficiency (AVED). We have determined the high-resolution crystal structure of human ATTP with (2R,4'R,8'R)-alpha-T in the binding pocket. Surprisingly, the ligand is sequestered deep in the hydrophobic core of the protein, implicating a large structural rearrangement for the entry and release of alpha-T. A comparison to the structure of a related protein, Sec14p, crystallized without a bona fide ligand, shows a possibly relevant open conformation for this family of proteins. Furthermore, of the known mutations that cause AVED, one mutation, L183P, is located directly in the binding pocket. Finally, three mutations associated with AVED involve arginine residues that are grouped together on the surface of ATTP. We propose that this positively charged surface may serve to orient an interacting protein, which might function to regulate the release of alpha-T through an induced change in conformation of ATTP.
Crystal structure of human alpha-tocopherol transfer protein bound to its ligand: implications for ataxia with vitamin E deficiency.,Min KC, Kovall RA, Hendrickson WA Proc Natl Acad Sci U S A. 2003 Dec 9;100(25):14713-8. Epub 2003 Dec 1. PMID:14657365[7]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Hentati A, Deng HX, Hung WY, Nayer M, Ahmed MS, He X, Tim R, Stumpf DA, Siddique T, Ahmed. Human alpha-tocopherol transfer protein: gene structure and mutations in familial vitamin E deficiency. Ann Neurol. 1996 Mar;39(3):295-300. PMID:8602747 doi:http://dx.doi.org/10.1002/ana.410390305
- ↑ Cavalier L, Ouahchi K, Kayden HJ, Di Donato S, Reutenauer L, Mandel JL, Koenig M. Ataxia with isolated vitamin E deficiency: heterogeneity of mutations and phenotypic variability in a large number of families. Am J Hum Genet. 1998 Feb;62(2):301-10. PMID:9463307 doi:S0002-9297(07)63495-8
- ↑ Ouahchi K, Arita M, Kayden H, Hentati F, Ben Hamida M, Sokol R, Arai H, Inoue K, Mandel JL, Koenig M. Ataxia with isolated vitamin E deficiency is caused by mutations in the alpha-tocopherol transfer protein. Nat Genet. 1995 Feb;9(2):141-5. PMID:7719340 doi:http://dx.doi.org/10.1038/ng0295-141
- ↑ Gotoda T, Arita M, Arai H, Inoue K, Yokota T, Fukuo Y, Yazaki Y, Yamada N. Adult-onset spinocerebellar dysfunction caused by a mutation in the gene for the alpha-tocopherol-transfer protein. N Engl J Med. 1995 Nov 16;333(20):1313-8. PMID:7566022
- ↑ Morley S, Panagabko C, Shineman D, Mani B, Stocker A, Atkinson J, Manor D. Molecular determinants of heritable vitamin E deficiency. Biochemistry. 2004 Apr 13;43(14):4143-9. PMID:15065857 doi:10.1021/bi0363073
- ↑ Mariotti C, Gellera C, Rimoldi M, Mineri R, Uziel G, Zorzi G, Pareyson D, Piccolo G, Gambi D, Piacentini S, Squitieri F, Capra R, Castellotti B, Di Donato S. Ataxia with isolated vitamin E deficiency: neurological phenotype, clinical follow-up and novel mutations in TTPA gene in Italian families. Neurol Sci. 2004 Jul;25(3):130-7. PMID:15300460 doi:10.1007/s10072-004-0246-z
- ↑ Min KC, Kovall RA, Hendrickson WA. Crystal structure of human alpha-tocopherol transfer protein bound to its ligand: implications for ataxia with vitamin E deficiency. Proc Natl Acad Sci U S A. 2003 Dec 9;100(25):14713-8. Epub 2003 Dec 1. PMID:14657365 doi:10.1073/pnas.2136684100
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