Noonan syndrome type I with PTPN11 3 bp deletion: structure-function implications.
Noonan syndrome was recently reported to be caused by mutations in the PTPN11 gene in 40% of the cases. This gene encodes the nonreceptor-type protein tyrosine phosphatase SHP-2 and has been shown to be self down-regulated with the concurrency of two SH2 domains. Insertion of a specific loop (D'EF) from N-terminal SH2 domain into the SHP-2 active-site is responsible for the reversible inhibition of the phosphatase activity. Here we report the first in frame trinucleotide deletion resulting in the removal of Aspartate 61 (D61del), a key residue of the N-terminal SH2 D'EF loop. Energetic-based structural analysis and electrostatic calculations carried out on the wild-type and mutant proteins predict lower stability of the D'EF loop for the D61del variant as compared to the wild type indicating better access to the active site and most likely an enzyme activated for longer extent. Similar computations were performed on the previously functionally characterized gain-of-function D61Y mutant and similar behaviors were observed. The simulation data for the D61del and D61Y mutants suggest that both variants could yield more catalytic cycles than the wild-type molecule in the same timespan because of the opening of the active site. It also supports the notion that D61 plays a major role for proper down-regulation of the protein tyrosine phosphatase activity of SHP-2.
Lee
Wen Hwa
WH
INSERM U428, Faculté des Sciences Pharmaceutiques et Biologiques, PARIS, France.
Raas-Rotschild
Annick
A
Miteva
Maria A
MA
Bolasco
Giulia
G
Rein
Azaria
A
Gillis
David
D
Vidaud
Dominique
D
Vidaud
Michel
M
Villoutreix
Bruno O
BO
Parfait
Beatrice
B
D000328:Adult; D020029:Base Pairing / Q000235:genetics*; D015536:Down-Regulation / Q000235:genetics; D005260:Female; D017353:Gene Deletion; D006801:Humans; D007231:Infant, Newborn; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry* / Q000235:genetics*; D008297:Male; D008958:Models, Molecular; D009010:Monte Carlo Method; D009634:Noonan Syndrome / Q000201:enzymology* / Q000235:genetics*; D010375:Pedigree; D017434:Protein Structure, Tertiary / Q000235:genetics; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry* / Q000235:genetics*; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D013329:Structure-Activity Relationship
D047908:Intracellular Signaling Peptides and Proteins; C516724:PTPN11 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases