PDBsum entry 4l96

Transcription/transcription inhibitor

PDB id: 4l96

Contents

Protein chain

260 a.a.

Ligands

LRG

Waters ×126

PDB id:

4l96

Name:

Transcription/transcription inhibitor

Title:

Structure of the complex between the f360l ppargamma mutant and the ligand lt175 (space group i222)

Structure:

Peroxisome proliferator-activated receptor gamma. Chain: a. Fragment: ligand binding domain (unp residues 235-505). Synonym: ppar-gamma, nuclear receptor subfamily 1 group c member 3. Engineered: yes. Mutation: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: pparg, nr1c3. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

2.38Å R-factor: 0.186 R-free: 0.226

Authors:

G.Pochetti,R.Montanari,D.Capelli,R.Chiaraluce,V.Consalvi,A.Pasquo, C.Lori,A.Laghezza,F.Loiodice

Key ref:

C.Lori et al. (2014). Structural basis of the transactivation deficiency of the human PPARγ F360L mutant associated with familial partial lipodystrophy. Acta Crystallogr D Biol Crystallogr, 70, 1965-1976. PubMed id: 25004973 DOI: 10.1107/S1399004714009638

Date:

18-Jun-13 Release date: 25-Jun-14

Protein chain

P37231  (PPARG_HUMAN) -  Peroxisome proliferator-activated receptor gamma from Homo sapiens

Seq: 505 a.a.

Struc: 260 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

DOI no: 10.1107/S1399004714009638

Acta Crystallogr D Biol Crystallogr 70:1965-1976 (2014)

PubMed id: 25004973

Structural basis of the transactivation deficiency of the human PPARγ F360L mutant associated with familial partial lipodystrophy.

C.Lori, A.Pasquo, R.Montanari, D.Capelli, V.Consalvi, R.Chiaraluce, L.Cervoni, F.Loiodice, A.Laghezza, M.Aschi, A.Giorgi, G.Pochetti.

ABSTRACT

The peroxisome proliferator-activated receptors (PPARs) are transcription factors that regulate glucose and lipid metabolism. The role of PPARs in several chronic diseases such as type 2 diabetes, obesity and atherosclerosis is well known and, for this reason, they are the targets of antidiabetic and hypolipidaemic drugs. In the last decade, some rare mutations in human PPARγ that might be associated with partial lipodystrophy, dyslipidaemia, insulin resistance and colon cancer have emerged. In particular, the F360L mutant of PPARγ (PPARγ2 residue 388), which is associated with familial partial lipodystrophy, significantly decreases basal transcriptional activity and impairs stimulation by synthetic ligands. To date, the structural reason for this defective behaviour is unclear. Therefore, the crystal structure of PPARγ F360L together with the partial agonist LT175 has been solved and the mutant has been characterized by circular-dichroism spectroscopy (CD) in order to compare its thermal stability with that of the wild-type receptor. The X-ray analysis showed that the mutation induces dramatic conformational changes in the C-terminal part of the receptor ligand-binding domain (LBD) owing to the loss of van der Waals interactions made by the Phe360 residue in the wild type and an important salt bridge made by Arg357, with consequent rearrangement of loop 11/12 and the activation function helix 12 (H12). The increased mobility of H12 makes the binding of co-activators in the hydrophobic cleft less efficient, thereby markedly lowering the transactivation activity. The spectroscopic analysis in solution and molecular-dynamics (MD) simulations provided results which were in agreement and consistent with the mutant conformational changes observed by X-ray analysis. Moreover, to evaluate the importance of the salt bridge made by Arg357, the crystal structure of the PPARγ R357A mutant in complex with the agonist rosiglitazone has been solved.