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From Proteopedia
Crystal structure of c-Src SH3 domain without ATCUN motif: monomer 2
Structural highlights
FunctionSRC_CHICK Non-receptor protein tyrosine kinase which is activated following engagement of many different classes of cellular receptors including immune response receptors, integrins and other adhesion receptors, receptor protein tyrosine kinases, G protein-coupled receptors as well as cytokine receptors. Participates in signaling pathways that control a diverse spectrum of biological activities including gene transcription, immune response, cell adhesion, cell cycle progression, apoptosis, migration, and transformation. Due to functional redundancy between members of the SRC kinase family, identification of the specific role of each SRC kinase is very difficult. SRC appears to be one of the primary kinases activated following engagement of receptors and plays a role in the activation of other protein tyrosine kinase (PTK) families. Receptor clustering or dimerization leads to recruitment of SRC to the receptor complexes where it phosphorylates the tyrosine residues within the receptor cytoplasmic domains. Plays an important role in the regulation of cytoskeletal organization through phosphorylation of specific substrates involved in this process. When cells adhere via focal adhesions to the extra-cellular matrix, signals are transmitted by integrins into the cell and result in tyrosine phosphorylation of a number of focal adhesion proteins, including PTK2/FAK1 and paxillin (PXN). Also active at the sites of cell-cell contact adherens junctions and at gap junctions. Implicated in the regulation of pre-mRNA-processing. Might be involved not only in mediating the transduction of mitogenic signals at the level of the plasma membrane but also in controlling progression through the cell cycle via interaction with regulatory proteins in the nucleus.[1] [2] Publication Abstract from PubMedMetal binding to sites engineered in proteins can provide an increase in their stability and facilitate new functions. Besides the sites introduced in purpose, sometimes they are present accidentally as a consequence of the expression system used to produce the protein. This happens with the copper- and nickel-binding (ATCUN) motif generated by the amino-terminal residues Gly-Ser-His. This ATCUN motif is fortuitously present in many proteins, but how it affects the structural and biophysical characterization of the proteins has not been studied. In this work, we have compared the structure and biophysical properties of a small modular domain, the SH3 domain of the c-Src tyrosine kinase, cloned with and without an ATCUN motif at the N terminus. At pH 7.0, the SH3 domain with the ATCUN motif binds nickel with a binding constant Ka = 28.0 +/- 3.0 mM(-1). The formation of the nickel complex increases the thermal and chemical stability of the SH3 domain. A comparison of the crystal structures of the SH3 domain with and without the ATCUN motif shows that the binding of nickel does not affect the overall structure of the SH3 domain. In all crystal structures analyzed, residues Gly-Ser-His in complex with Ni(2+) show a square planar geometry. The CD visible spectrum of the nickel complex shows that this geometry is also present in the solution. Therefore, our results not only show that the ATCUN motif might influence the biophysical properties of the protein, but also points to an advantageous stabilization of the protein with potential biotechnological applications. The effect of an engineered ATCUN motif on the structure and biophysical properties of the SH3 domain of c-Src tyrosine kinase.,Plaza-Garrido M, Salinas-Garcia MC, Martinez JC, Camara-Artigas A J Biol Inorg Chem. 2020 Apr 11. pii: 10.1007/s00775-020-01785-0. doi:, 10.1007/s00775-020-01785-0. PMID:32279137[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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