1a1c
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C-SRC (SH2 DOMAIN) COMPLEXED WITH ACE-PHOSPHOTYR-GLU-(N-ME(-(CH2)3-CYCLOPENTYL))
OverviewOverview
Thermodynamic measurements, structural determinations, and molecular, computations were applied to a series of peptide ligands of the, pp60(c-src) SH2 domain in an attempt to understand the critical binding, determinants for this class of molecules. Isothermal titration calorimetry, (ITC) measurements were combined with structural data derived from X-ray, crystallographic studies on 12 peptide-SH2 domain complexes. The peptide, ligands studied fall into two general classes: (1) dipeptides of the, general framework N-acetylphosphotyrosine (or phosphotyrosine, replacement)-Glu or methionine (or S-methylcysteine)-X, where X represents, a hydrophobic amine, and (2) tetra- or pentapeptides of the general, framework N-acetylphosphotyrosine-Glu-Glu-Ile-X, where X represents either, Glu, Gln, or NH2. Dipeptide analogs which featured X as either, hexanolamine or heptanolamine were able to pick up new hydrogen bonds, involving their hydroxyl groups within a predominantly lipophilic surface, cavity. However, due to internal strain as well as the solvent, accessibility of the new hydrogen bonds formed, no net increase in binding, affinity was observed. Phosphatase-resistant benzylmalonate and, alpha,alpha-difluorobenzyl phosphonate analogs of phosphotyrosine retained, some binding affinity for the pp60(c-src) SH2 domain but caused local, structural perturbations in the phosphotyrosine-binding site. In the case, where a reversible covalent thiohemiacetal was formed between a formylated, phosphotyrosine analog and the thiol side chain of Cys-188, deltaS was, 25.6 cal/(mol K) lower than for the nonformylated phosphotyrosine parent., Normal mode calculations show that the dramatic decrease in entropy, observed for the covalent thiohemiacetal complex is due to the inability, of the phosphotyrosine moiety to transform lost rotational and, translational degrees of freedom into new vibrational modes.
DiseaseDisease
Known disease associated with this structure: Colon cancer, advanced OMIM:[190090]
About this StructureAbout this Structure
1A1C is a Single protein structure of sequence from Homo sapiens with ACE as ligand. Active as Transferase, with EC number and 2.7.10.2 2.7.10.1 and 2.7.10.2 Full crystallographic information is available from OCA.
ReferenceReference
Peptide ligands of pp60(c-src) SH2 domains: a thermodynamic and structural study., Charifson PS, Shewchuk LM, Rocque W, Hummel CW, Jordan SR, Mohr C, Pacofsky GJ, Peel MR, Rodriguez M, Sternbach DD, Consler TG, Biochemistry. 1997 May 27;36(21):6283-93. PMID:9174343
Page seeded by OCA on Mon Nov 12 15:54:11 2007