Protein Domain : SH3-like domain, bacterial-type IPR003646

Type	Domain
Description	SH3 (src Homology-3) domains are small protein modules containing approximately 50 amino acid residues [ , ]. They are found in a great variety of intracellular or membrane-associated proteins [, , ] for example, in a variety of proteins with enzymatic activity, in adaptor proteins, such as fodrin and yeast actin binding protein ABP-1.The SH3 domain has a characteristic fold which consists of five or six β-strands arranged as two tightly packed anti-parallel β-sheets. The linker regions may contain short helices. The surface of the SH3-domain bears a flat, hydrophobic ligand-binding pocket which consists of three shallow grooves defined by conservative aromatic residues in which the ligand adopts an extended left-handed helical arrangement. The ligand binds with low affinity but this may be enhanced by multiple interactions. The region bound by the SH3 domain is in all cases proline-rich and contains PXXP as a core-conserved binding motif. The function of the SH3 domain is not well understood but they may mediate many diverse processes such as increasing local concentration of proteins, altering their subcellular location and mediating the assembly of large multiprotein complexes [ ].SH3 domains are widespread among metazoan intracellular signalling proteins and typically bind proline-richpolypeptides. This SH3 domain is a prokaryotic homologue. It might have two possible functions: (1) promoting survival of a pathogen withinthe invaded cell by modulating pathways controlled by SH3 domains; or (2) promoting invasion by binding to receptors on eukaryotic cells [, ].
Short Name	SH3-like_bac-type