PDBsum entry 4le9

Transferase

PDB id: 4le9

Contents

Protein chain

59 a.a.

Ligands

PGE

Waters ×62

References listed in PDB file

Key reference

• Title: 3d domain swapping in a chimeric c-Src sh3 domain takes place through two hinge loops.
• Authors: A.Cámara-Artigas, S.Martínez-Rodríguez, E.Ortiz-Salmerón, J.M.Martín-García.
• Ref.: J Struct Biol, 2014, 186, 195-203. [DOI no: 10.1016/j.jsb.2014.02.007]
• PubMed id: 24556574

Abstract

In the Src Homology 3 domain (SH3) the RT and n-Src loops form a pocket that accounts for the specificity and affinity in binding of proline rich motifs (PRMs), while the distal and diverging turns play a key role in the folding of the protein. We have solved the structure of a chimeric mutant c-Src-SH3 domain where specific residues at the RT- and n-Src-loops have been replaced by those present in the corresponding Abl-SH3 domain. Crystals of the chimeric protein show a single molecule in the asymmetric unit, which appears in an unfolded-like structure that upon generation of the symmetry related molecules reveals the presence of a domain swapped dimer where both, RT- and n-Src loops, act as hinge loops. In contrast, the fold of the diverging type II β-turn and the distal loop are well conserved. Our results are the first evidence for the presence of a structured diverging type II β-turn in an unfolded-like intermediate of the c-Src-SH3 domain, which can be stabilized by interactions from the β-strands of the same polypeptide chain or from a neighboring one. Futhermore, this crystallographic structure opens a unique opportunity to study the effect of the amino acid sequence of the hinge loops on the 3D domain swapping process of c-Src-SH3.