3I9Q

Crystal Structure of the triple mutant S19G-P20D-R21S of alpha spectrin SH3 domain

Summary for 3I9Q

• Entry DOI: 10.2210/pdb3i9q/pdb
• Descriptor: Spectrin alpha chain, SULFATE ION (3 entities in total)
• Functional Keywords: sh3-like barrel, actin capping, actin-binding, calmodulin-binding, cytoskeleton, phosphoprotein, sh3 domain, structural protein
• Biological source: Gallus gallus (bantam,chickens)
• Cellular location: Cytoplasm, cytoskeleton: P07751
• Total number of polymer chains: 1
• Total formula weight: 6709.59

Authors

Camara-Artigas, A.,Gavira, J.A. (deposition date: 2009-07-12, release date: 2009-12-15, Last modification date: 2023-09-06)

Primary citation

Camara-Artigas, A.,Andujar-Sanchez, M.,Ortiz-Salmeron, E.,Cuadri, C.,Casares, S.
The effect of a proline residue on the rate of growth and the space group of alpha-spectrin SH3-domain crystals.
Acta Crystallogr.,Sect.D, 65:1247-1252, 2009

PubMed Abstract: alpha-Spectrin SH3-domain (Spc-SH3) crystallization is characterized by very fast growth of the crystals in the presence of ammonium sulfate as a precipitant agent. The origin of this behaviour can be attributed to the presence of a proline residue that participates in a crystal contact mimicking the binding of proline-rich sequences to SH3 domains. This residue, Pro20, is located in the RT loop and is the main contact in one of the interfaces present in the orthorhombic Spc-SH3 crystal structures. In order to understand the molecular interactions that are responsible for the very fast crystal growth of the wild-type (WT) Spc-SH3 crystals, the crystal structure of a triple mutant in which the residues Ser19-Pro20-Arg21 in the RT loop have been replaced by Gly19-Asp20-Ser21 (GDS Spc-SH3 mutant) has been solved. The removal of the critical proline residue results in slower nucleation of the Spc-SH3 crystals and a different arrangement of the protein molecules in the unit cell, leading to a crystal that belongs to the tetragonal space group P4(1)2(1)2, with unit-cell parameters a = b = 42.231, c = 93.655 A, and that diffracts to 1.45 A resolution. For both WT Spc-SH3 and the GDS mutant, light-scattering experiments showed that a dimer was formed in solution within a few minutes of the addition of 2 M ammonium sulfate at pH 6.5 and allowed the proposal of a mechanism for the nucleation and crystal growth of Spc-SH3 in which the Pro20 residue plays a key role in the rate of crystal growth.

PubMed: 19966410
DOI: 10.1107/S0907444909038037

Experimental method

X-RAY DIFFRACTION (1.45 Å)