Characterization and functional analysis of the nucleotide binding fold in human peroxisomal ATP binding cassette transporters.
The 70-kDa peroxisomal membrane protein (PMP70) and the adrenoleukodystrophy protein (ALDP) are half ATP binding cassette (ABC) transporters in the peroxisome membrane. Mutations in the ALD gene encoding ALDP result in the X-linked neurodegenerative disorder adrenoleukodystrophy. Plausible models exist to show a role for ATP hydrolysis in peroxisomal ABC transporter functions. Here, we describe the first measurements of the rate of ATP binding and hydrolysis by purified nucleotide binding fold (NBF) fusion proteins of PMP70 and ALDP. Both proteins act as an ATP specific binding subunit releasing ADP after ATP hydrolysis; they did not exhibit GTPase activity. Mutations in conserved residues of the nucleotidases (PMP70: G478R, S572I; ALDP: G512S, S606L) altered ATPase activity. Furthermore, our results indicate that these mutations do not influence homodimerization or heterodimerization of ALDP or PMP70. The study provides evidence that peroxisomal ABC transporters utilize ATP to become a functional transporter.
Roerig
P
P
Zentrum für Kinderheilkunde, Department of Pediatrics, Heinrich Heine University, Düsseldorf, Germany.
Mayerhofer
P
P
Holzinger
A
A
Gärtner
J
J
D000074063:ATP Binding Cassette Transporter, Subfamily D, Member 1; D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D004926:Escherichia coli; D020558:GTP Phosphohydrolases / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D020675:Peroxisomes / Q000378:metabolism*; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid
C115572:ABCD1 protein, human; C063305:ABCD3 protein, human; D000074063:ATP Binding Cassette Transporter, Subfamily D, Member 1; D018528:ATP-Binding Cassette Transporters; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D020558:GTP Phosphohydrolases