PDBsum entry 1xwh

Transcription

PDB id: 1xwh

Contents

Protein chain

66 a.a. *

Metals

_ZN ×2

* Residue conservation analysis

PDB id:

1xwh

Name:

Transcription

Title:

Nmr structure of the first phd finger of autoimmune regulator protein (aire1): insights into apeced

Structure:

Autoimmune regulator. Chain: a. Fragment: first phddomain. Synonym: autoimmune polyendocrinopathy candidiasis ectodermal dystrophy protein, apeced protein. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: aire1. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

NMR struc:

20 models

Authors:

M.J.Bottomley,G.Stier,J.Krasotkina,G.Legube,B.Simon,A.Akhtar, M.Sattler,G.Musco

Key ref:

M.J.Bottomley et al. (2005). NMR structure of the first PHD finger of autoimmune regulator protein (AIRE1). Insights into autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) disease. J Biol Chem, 280, 11505-11512. PubMed id: 15649886 DOI: 10.1074/jbc.M413959200

Date:

01-Nov-04 Release date: 25-Jan-05

Protein chain

O43918  (AIRE_HUMAN) -  Autoimmune regulator from Homo sapiens

Seq: 545 a.a.

Struc: 66 a.a.*

* PDB and UniProt seqs differ at 4 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1074/jbc.M413959200

J Biol Chem 280:11505-11512 (2005)

PubMed id: 15649886

NMR structure of the first PHD finger of autoimmune regulator protein (AIRE1). Insights into autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) disease.

M.J.Bottomley, G.Stier, D.Pennacchini, G.Legube, B.Simon, A.Akhtar, M.Sattler, G.Musco.

ABSTRACT

Mutations in the autoimmune regulator protein AIRE1 cause a monogenic autosomal recessively inherited disease: autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED). AIRE1 is a multidomain protein that harbors two plant homeodomain (PHD)-type zinc fingers. The first PHD finger of AIRE1 is a mutational hot spot, to which several pathological point mutations have been mapped. Using heteronuclear NMR spectroscopy, we determined the solution structure of the first PHD finger of AIRE1 (AIRE1-PHD1), and characterized the peptide backbone mobility of the domain. We performed a conformational analysis of pathological AIRE1-PHD1 mutants that allowed us to rationalize the structural impact of APECED-causing mutations and to identify an interaction site with putative protein ligands of the AIRE1-PHD1 domain. The structure unequivocally exhibits the canonical PHD finger fold, with a highly conserved tryptophan buried inside the structure. The PHD finger is stabilized by two zinc ions coordinated in an interleaved (cross-brace) scheme. This zinc coordination resembles RING finger domains, which can function as E3 ligases in the ubiquitination pathway. Based on this fold similarity, it has been suggested that PHD fingers might also function as E3 ligases, although this hypothesis is controversial. At variance to a previous report, we could not find any evidence that AIRE1-PHD1 has an intrinsic E3 ubiquitin ligase activity, nor detect any direct interaction between AIRE1-PHD1 and its putative cognate E2. Consistently, we show that the AIRE1-PHD1 structure is clearly distinct from the RING finger fold. Our results point to a function of the AIRE1-PHD1 domain in protein-protein interactions, which is impaired in some APECED mutations.

Selected figure(s)

Figure 1.
FIG. 1. The three-dimensional structure of the AIRE1-PHD1 domain. A, multiple sequence alignment of PHD and RING finger domains. Zinc-binding residues and the conserved Trp are marked with asterisks (*). Sites of APECED-causing mutations are marked with a red plus (+). Secondary structure elements of AIRE1-PHD1 are shown above the alignment. B, stereo-view representation of the backbone atoms (N, C , C') for residues 295-344 of an NMR ensemble of 20 structures. Secondary structure elements are in blue, the loops and random coil in gray, the variable loop L3 in yellow, the zinc ions in pink, and the commonly conserved Trp residue side chain in cyan. C, ribbon representation of AIRE1-PHD1 (same orientation as B, showing the side chains (cyan) and atoms (sulfur in yellow, nitrogen in green) of the zinc-coordinating residues, plus the conserved Trp335 (cyan).

Figure 5.
FIG. 5. Location and structural effects of APECED causing mutations. 1H-1D spectra (amide region) of pathological mutants of AIRE1-PHD1 and of wild-type AIRE1-PHD1 and AIRE1-PHD2. A, mutant C311Y; B, AIRE1-PHD1 wild type upon addition of 20 mM EDTA; C, mutant P326Q; D, mutant P326L; asterisks indicate the presence of additional conformers, possibly coming from a cis-trans isomerization of P325; E, mutant V301M; F, wild-type AIRE1 PHD1, and G, wild-type AIRE1-PHD2; H, ribbon representation of the AIRE1-PHD1 structure (blue) and mapping of pathological point mutations by showing their side chains in red; the zinc-binding residues are in cyan, the cis-proline Pro325 in yellow, and the zinc ions in pink. I, space-filled representation of AIRE1-PHD1, with pathological mutation sites in red, Pro325 in yellow and zinc ions in pink. Val301 and Pro326 are partially exposed to the surface.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2005, 280, 11505-11512) copyright 2005.

Figures were selected by the author.