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3.A.1.203.3
The peroxysomal long chain fatty acid (LCFA) half transporter, ABCD1 (ALD, ALDP, the X-linked adrenoleukodystrophy (X-ALD or ALDP) protein) (functions as a homodimer and accepts acyl-CoA esters (van Roermund et al. 2008)). It transports C24:0 and C26:0 fatty acids and their CoA-derivatives as substrates (van Roermund et al., 2011; Jia et al. 2022).  ABCD1 deficiency or mutation is associated with plasma and tissue elevation of C24:0 and C26:0 accompanied by demyelination and inflamation (Baarine et al. 2012).  X-ALD is a recessive neurodegenerative disorder that affects the brain's white matter and is associated with adrenal insufficiency. It is characterized by abnormal function of peroxisomes, which leads to an accumulation of very long-chain fatty acids (VLCFA) in plasma and tissues, especially in the cortex of the adrenal glands and the white matter of the central nervous system, causing demyelinating disease and adrenocortical insufficiency (Addison's disease or X-linked adrenoleukodystrophy (X-ALD) (Kallabi et al. 2013; Andreoletti et al. 2017) The system forms heterodimers with PMP70 (ABCD3; TC#3.A.1.203.1) (Hillebrand et al. 2007). X-ALD, the most common peroxisomal disorder, results from mutations in ABCD1 (ALDP) (Margoni et al. 2017). The structure and function of the ABCD1 variant database have been described (Mallack et al. 2022). This peroxisomal very long chain fatty acid (VLCFA) transporter is central to fatty acid catabolism and lipid biosynthesis. Its dysfunction underlies toxic cytosolic accumulation of VLCFAs, progressive demyelination, and neurological impairment including X-ALD. Le et al. 2022 presented cryo-EM structures of ABCD1 in phospholipid nanodiscs in a nucleotide bound conformation open to the peroxisomal lumen and an inward facing conformation open to the cytosol at up to 3.5 Å resolution, revealing details of its transmembrane cavity and ATP- dependent conformational spectrum. They identified features distinguishing ABCD1 from its closest homologs and showed that coenzyme A (CoA) esters of VLCFAs modulate ABCD1 activity in a species dependent manner. A transport mechanism was suggested in which the CoA moieties of VLCFA-CoAs enter the hydrophilic transmembrane domain while the acyl chains extend out into the surrounding membrane bilayer. The structures help rationalize disease causing mutations (Le et al. 2022). Three cryogenic EM structures of ABCD1: the apo-form, substrate- and ATP-bound forms have been solved (Chen et al. 2022). Distinct from what was seen in the previously reported ABC transporters, the two symmetric molecules of behenoyl coenzyme A (C22:0-CoA) cooperatively bind to the transmembrane domains (TMDs). For each C22:0-CoA, the hydrophilic 3'-phospho-ADP moiety of the CoA portion inserts into one TMD, with the succeeding pantothenate and cysteamine moiety crossing the inter-domain cavity, whereas the hydrophobic fatty acyl chain extends to the opposite TMD. Structural analysis combined with biochemical assays illustrated snapshots of the ABCD1-mediated substrate transport cycle (Chen et al. 2022). Jia et al. 2022 reported the cryo-EM structure of human ALDP at 3.4 Å resolution. ALDP exhibits a cytosolic-facing conformation. Compared to other lipid ATP-binding cassette transporters, ALDP has two substrate binding cavities formed within the transmembrane domains. Such structural organization may be suitable for the coordination of VLCFAs. X-ALD is caused by a mutation in the ABCD1 gene, encoding a peroxisomal protein, which has various clinical manifestations and a rapid progression from initial symptoms to fatal inflammatory demyelination (Yu et al. 2022). Structural insights into substrate recognition and translocation of human peroxisomal ABC transporter, ALDP, have appeared (Xiong et al. 2023). An innovative tree-based method for sampling molecular conformations allows prediction of conformations (Haschka et al. 2024).

Accession Number:P33897
Protein Name:ABCD1 aka ALD
Length:745
Molecular Weight:82937.00
Species:Homo sapiens (Human) [9606]
Number of TMSs:4
Location1 / Topology2 / Orientation3: Peroxisome membrane1 / Multi-pass membrane protein2
Substrate long-chain fatty acid

Cross database links:

RefSeq: NP_000024.2   
Entrez Gene ID: 215   
Pfam: PF06472    PF00005   
OMIM: 300100  phenotype
300371  gene
300475  phenotype
KEGG: hsa:215   

Gene Ontology

GO:0005779 C:integral to peroxisomal membrane
GO:0005524 F:ATP binding
GO:0042626 F:ATPase activity, coupled to transmembrane m...
GO:0042802 F:identical protein binding
GO:0005325 F:peroxisomal fatty acyl CoA transporter acti...
GO:0033540 P:fatty acid beta-oxidation using acyl-CoA ox...
GO:0015919 P:peroxisomal membrane transport
GO:0007031 P:peroxisome organization

References (30)

[1] “Putative X-linked adrenoleukodystrophy gene shares unexpected homology with ABC transporters.”  Mosser J.et.al.   8441467
[2] “The DNA sequence of the human X chromosome.”  Ross M.T.et.al.   15772651
[3] “The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).”  The MGC Project Teamet.al.   15489334
[4] “Homo- and heterodimerization of peroxisomal ATP-binding cassette half-transporters.”  Liu L.X.et.al.   10551832
[5] “Characterization and functional analysis of the nucleotide binding fold in human peroxisomal ATP binding cassette transporters.”  Roerig P.et.al.   11248239
[6] “Adrenoleukodystrophy gene: unexpected homology to a protein involved in peroxisome biogenesis.”  Aubourg P.et.al.   8507690
[7] “Human adrenoleukodystrophy protein and related peroxisomal ABC transporters interact with the peroxisomal assembly protein PEX19p.”  Gloeckner C.J.et.al.   10777694
[8] “PEX19 binds multiple peroxisomal membrane proteins, is predominantly cytoplasmic, and is required for peroxisome membrane synthesis.”  Sacksteder K.A.et.al.   10704444
[9] “Mutations in the adrenoleukodystrophy gene.”  Dodd A.et.al.   9195223
[10] “ABCD1 mutations and the X-linked adrenoleukodystrophy mutation database: role in diagnosis and clinical correlations.”  Kemp S.et.al.   11748843
[11] “Evaluation of the low-specificity protease elastase for large-scale phosphoproteome analysis.”  Wang B.et.al.   19007248
[12] “Kinase-selective enrichment enables quantitative phosphoproteomics of the kinome across the cell cycle.”  Daub H.et.al.   18691976
[13] “A quantitative atlas of mitotic phosphorylation.”  Dephoure N.et.al.   18669648
[14] “Abnormal messenger RNA expression and a missense mutation in patients with X-linked adrenoleukodystrophy.”  Cartier N.et.al.   7904210
[15] “Missense mutations are frequent in the gene for X-chromosomal adrenoleukodystrophy (ALD).”  Fuchs S.et.al.   7849723
[16] “Identification of mutations in the putative ATP-binding domain of the adrenoleukodystrophy gene.”  Fanen P.et.al.   8040304
[17] “Spectrum of mutations in the gene encoding the adrenoleukodystrophy protein.”  Ligtenberg M.J.L.et.al.   7825602
[18] “Mutations in the gene for X-linked adrenoleukodystrophy in patients with different clinical phenotypes.”  Braun A.et.al.   7717396
[19] “Mutational analysis of patients with X-linked adrenoleukodystrophy.”  Kok F.et.al.   7581394
[20] “Mutational and protein analysis of patients and heterozygous women with X-linked adrenoleukodystrophy.”  Feigenbaum V.et.al.   8651290
[21] “Identification of mutations in the ALD-gene of 20 families with adrenoleukodystrophy/adrenomyeloneuropathy.”  Krasemann E.W.et.al.   8566952
[22] “First missense mutation (W679R) in exon 10 of the adrenoleukodystrophy gene in siblings with adrenomyeloneuropathy.”  Korenke G.C.et.al.   9452087
[23] “X-linked adrenomyeloneuropathy associated with 14 novel ALD-gene mutations: no correlation between type of mutation and age of onset.”  Wichers M.et.al.   10480364
[24] “Two novel missense mutations causing adrenoleukodystrophy in Italian patients.”  Perusi C.et.al.   10369742
[25] “Determination of 30 X-linked adrenoleukodystrophy mutations, including 15 not previously described.”  Lachtermacher M.B.et.al.   10737980
[26] “Detection of mutations in the ALD gene (ABCD1) in seven Italian families: description of four novel mutations.”  Lira M.G.et.al.   10980539
[27] “Eight novel ABCD1 gene mutations and three polymorphisms in patients with X-linked adrenoleukodystrophy: the first polymorphism causing an amino acid exchange.”  Dvorakova L.et.al.   11438993
[28] “Characterisation of two mutations in the ABCD1 gene leading to low levels of normal ALDP.”  Guimaraes C.P.et.al.   11810273
[29] “Contiguous deletion of the X-linked adrenoleukodystrophy gene (ABCD1) and DXS1357E: a novel neonatal phenotype similar to peroxisomal biogenesis disorders.”  Corzo D.et.al.   11992258
[30] “Identification of seven novel mutations in ABCD1 by a DHPLC-based assay in Italian patients with X-linked adrenoleukodystrophy.”  Montagna G.et.al.   15643618

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FASTA formatted sequence
1:	MPVLSRPRPW RGNTLKRTAV LLALAAYGAH KVYPLVRQCL APARGLQAPA GEPTQEASGV 
61:	AAAKAGMNRV FLQRLLWLLR LLFPRVLCRE TGLLALHSAA LVSRTFLSVY VARLDGRLAR 
121:	CIVRKDPRAF GWQLLQWLLI ALPATFVNSA IRYLEGQLAL SFRSRLVAHA YRLYFSQQTY 
181:	YRVSNMDGRL RNPDQSLTED VVAFAASVAH LYSNLTKPLL DVAVTSYTLL RAARSRGAGT 
241:	AWPSAIAGLV VFLTANVLRA FSPKFGELVA EEARRKGELR YMHSRVVANS EEIAFYGGHE 
301:	VELALLQRSY QDLASQINLI LLERLWYVML EQFLMKYVWS ASGLLMVAVP IITATGYSES 
361:	DAEAVKKAAL EKKEEELVSE RTEAFTIARN LLTAAADAIE RIMSSYKEVT ELAGYTARVH 
421:	EMFQVFEDVQ RCHFKRPREL EDAQAGSGTI GRSGVRVEGP LKIRGQVVDV EQGIICENIP 
481:	IVTPSGEVVV ASLNIRVEEG MHLLITGPNG CGKSSLFRIL GGLWPTYGGV LYKPPPQRMF 
541:	YIPQRPYMSV GSLRDQVIYP DSVEDMQRKG YSEQDLEAIL DVVHLHHILQ REGGWEAMCD 
601:	WKDVLSGGEK QRIGMARMFY HRPKYALLDE CTSAVSIDVE GKIFQAAKDA GIALLSITHR 
661:	PSLWKYHTHL LQFDGEGGWK FEKLDSAARL SLTEEKQRLE QQLAGIPKMQ RRLQELCQIL 
721:	GEAVAPAHVP APSPQGPGGL QGAST