Sequence and structural alignment of homologous SH2 domains.

<p>(A) Structure and domain arrangement in full-length Csk (PDB ID 1K9A). (B) Sequence and structural alignment of SH2 domains of homologous protein kinases: Itk (red), Src (blue), Csk (green) illustrating the stark differential loop lengths among these domains. Most notably, Csk possesses the shortest CD loop (turn) of the three modular domains. Sequence alignment was performed using Clustal Omega through UniProt web server. Structural alignment was performed in PyMol using PDB entries 2ETZ, 2SRC, and 3EAC for Itk, Src, and Csk, respectively.