The AXH module: an independently folded domain common to ataxin-1 and HBP1.
Ataxin-1 (ATX1), a human protein responsible for spinocerebellar ataxia type 1 in humans, shares a region of homology, named AXH module, with the apparently unrelated transcription factor HBP1. Here, we describe the first characterisation of the AXH module in terms of its structural properties and stability. By producing protein constructs spanning the AXH modules of ATX1 and HBP1 and by comparing their properties, we have identified the minimal region sufficient for forming independently folded units (domains). Knowledge of the AXH domain boundaries allows us to map many of the interactions of ATX1 with other molecules onto the AXH module. We further show that the AXH of ATX1 is a dimerisation domain and is able to recognise RNA with the same nucleotide preference previously described for the full-length protein. AXH is therefore a novel protein-protein and RNA binding motif.
de Chiara
C
C
National Institute for Medical Research, The Ridgeway, NW71AA London, UK.
Giannini
C
C
Adinolfi
S
S
de Boer
J
J
Guida
S
S
Ramos
A
A
Jodice
C
C
Kioussis
D
D
Pastore
A
A
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D000067696:Ataxin-1; D000067528:Ataxins; D004268:DNA-Binding Proteins / Q000737:chemistry*; D019281:Dimerization; D006801:Humans; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry*; D009687:Nuclear Proteins / Q000737:chemistry*; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D016601:RNA-Binding Proteins / Q000737:chemistry; D016415:Sequence Alignment
C000593749:ATXN1 protein, human; D000067696:Ataxin-1; D000067528:Ataxins; D004268:DNA-Binding Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; C062189:histone DNA binding protein-1