Abstract:
:Thermodynamics and kinetics of the interaction between T cell receptor specific for cytomegalovirus peptide (TCR(CMV)) and its specific ligand, pp65-HLA-A*0201 complex, were studied by surface plasmon resonance and stopped-flow methods. In the latter measurements, fluorescence resonance energy transfer (FRET) between fluorescently labeled reactants was used. Thermodynamic data derived from surface plasmon resonance measurements suggest that the complex formation is driven by both favorable enthalpy and entropy. Two reaction phases were resolved by the stopped-flow measurements. The rate constant of the first step was calculated to be close to the diffusion-controlled limit rate (3x10(5) to 10(6) M(-1) s(-1)), whereas the second step's reaction rate was found to be concentration independent and relatively slow (2-4 s(-1) at 25 degrees C). These findings strongly suggest that the interactions between the TCR and its ligand, the peptide-MHC complex, proceed by a two-step mechanism, in which the second step is an induced-fit process, rate determining for antigen recognition by TCR.
journal_name
Proc Natl Acad Sci U S Aauthors
Gakamsky DM,Lewitzki E,Grell E,Saulquin X,Malissen B,Montero-Julian F,Bonneville M,Pecht Idoi
10.1073/pnas.0707061104subject
Has Abstractpub_date
2007-10-16 00:00:00pages
16639-44issue
42eissn
0027-8424issn
1091-6490pii
0707061104journal_volume
104pub_type
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