This title appears in the Scientific Report :
2006
Please use the identifier:
http://hdl.handle.net/2128/2539 in citations.
NMR-Lösungsstruktur der humanen HCK SH3-Domäne im Komplex mit einem artifiziellen, hochaffinen Peptid-Liganden
NMR-Lösungsstruktur der humanen HCK SH3-Domäne im Komplex mit einem artifiziellen, hochaffinen Peptid-Liganden
The hematopoietic cell kinase Hck is a cytosolic protein-tyrosine kinase, which is involved in numerous signal transduction pathways and plays a significant role in immunogenic diseases like AIDS or leukemia. Hck interacts via its SH3 domain with other cellular or viral proteins resulting in regulat...
Saved in:
Personal Name(s): | Schmidt, Holger (Coresponding author) |
---|---|
Contributing Institute: |
Biologische Strukturforschung; IBI-2 |
Imprint: |
Jülich
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
2006
|
Physical Description: |
XII, 115 S. |
Dissertation Note: |
Universität Düsseldorf, Diss., 2006 |
ISBN: |
3-89336-441-2 |
Document Type: |
Book Dissertation / PhD Thesis |
Research Program: |
Funktion und Dysfunktion des Nervensystems |
Series Title: |
Schriften des Forschungszentrums Jülich. Reihe Lebenswissenschaften / Life Sciences
28 |
Subject (ZB): | |
Link: |
OpenAccess |
Publikationsportal JuSER |
The hematopoietic cell kinase Hck is a cytosolic protein-tyrosine kinase, which is involved in numerous signal transduction pathways and plays a significant role in immunogenic diseases like AIDS or leukemia. Hck interacts via its SH3 domain with other cellular or viral proteins resulting in regulation of kinase activity. Thus, the identification of the parameters responsible for the binding to other proteins is essential for understanding of protein-protein interactions as well as for the development of new drugs that would specifically inhibit these interactions. Aim of this work was the determination of the solution structure of Hck SH3 domain (HckSH3) in complex with an artificial high affinity peptide ligand (PD1). Although some HckSH3 interaction studies were accomplished, this work presents the first complex structure of HckSH3. The binding properties of HckSH3 were of particular interest, especially because the PD1 peptide shows an unusual amino acid sequence for a ligand to Src type SH3 domains, not in accordance with their consensus sequence. Instead the basic anchor residue usually found at position P$_{−3}$ the PD1 peptide exhibits a hydrophobic tyrosine residue (Tyr4), while a basic leucine residue is positioned at P$_{−4}$. Nevertheless, the PD1 peptid binds to HckSH3 with a surprisingly high affinity as can be seen by the measured K$_{D}$ value of 0.23 μM, which ranges among the most affine binders known for SH3 peptide ligands. The solution structure of the complex reveals the typical poly-proline helix conformation for the peptide residues Leu6 to Pro10. A comparison to other HckSH3 structures shows that the peptide adopts a class I’ binding conformation, and no significant conformational changes in the overall structure of HckSH3 can be recognized. The most prominent feature is the formation of a short antiparallel $\beta$-sheet in the RT loop of HckSH3 upon PD1 binding, which is not present in any other structure of HckSH3. This $\beta$-sheet is characterized by the formation of hydrogen bond interactions between the carbonyl and amide groups of the HckSH3 residues Y88 and F98 within the RT loop. H$_{2}$O/D$_{2}$O amide proton exchange experiments revealed an increase in exchange lifetimes of the protons involved in hydrogen bonding throughout the whole HckSH3 upon ligand binding, indicating that the PD1 interaction stabilises the overall structure of HckSH3. Comparisons of the complex to other SH3:ligand complexes reveal the untypical binding mode of the aminoterminal PD1 residues to the HckSH3 compass pocket region. Due to a kink in the peptide backbone, the basic side chain of Lys3 at position P$_{−4}$ points into the HckSH3 compass pocket and seems to fulfill the function of the anchor residue. The hydrophobic ring of peptide residue Tyr4 provides extensive contacts to the imidazole ring of H92 in the HckSH3 RT loop. In case of the PD1 peptide the described new ligand recognition mode of HckSH3 results in a high affinity binding. Algorithms for the prediction of ligand binding to SH3 domains like SH3-SPOT fail to identify PD1 as high affinity ligand. Therefore, it seems to be necessary to reconsider the consensus sequence of Src type SH3 domains. This shows the important contribution of the HckSH3:PD1 complex structure in understanding the molecular basics of SH3-ligand interactions. Additionally this knowledge is prerequisite for development of more reliable algorithms for the prediction of SH3-binding proteins as well as for drug design. |