Journal: Proteins / Year: 2019 Title: Mutation in a flexible linker modulates binding affinity for modular complexes. Authors: Philippa H Stokes / Neil O Robertson / Ana P G Silva / Tanya Estephan / Jill Trewhella / J Mitchell Guss / Jacqueline M Matthews / Abstract: Tandem beta zippers are modular complexes formed between repeated linear motifs and tandemly arrayed domains of partner proteins in which β-strands form upon binding. Studies of such complexes, ...Tandem beta zippers are modular complexes formed between repeated linear motifs and tandemly arrayed domains of partner proteins in which β-strands form upon binding. Studies of such complexes, formed by LIM domain proteins and linear motifs in their intrinsically disordered partners, revealed spacer regions between the linear motifs that are relatively flexible but may affect the overall orientation of the binding modules. We demonstrate that mutation of a solvent exposed side chain in the spacer region of an LHX4-ISL2 complex has no significant effect on the structure of the complex, but decreases binding affinity, apparently by increasing flexibility of the linker.
A: LIM/homeobox protein Lhx4,Insulin gene enhancer protein ISL-2 hetero molecules
defined by author&software
Evidence: SAXS, Light scattering and SAXS data indicate that the molecule is monomeric ion solution. SAXS data indicates a more elongated structure indicating that the extreme bend in the structure ...Evidence: SAXS, Light scattering and SAXS data indicate that the molecule is monomeric ion solution. SAXS data indicates a more elongated structure indicating that the extreme bend in the structure is a crystallization artefact
The authors state that light scattering and SAXS data indicate that the molecule is monomeric ion solution. SAXS data indicates a more elongated structure indicating that the extreme bend in the structure is a crystallization artifact.
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Components
#1: Protein
LIM/homeoboxproteinLhx4,InsulingeneenhancerproteinISL-2 / LIM homeobox protein 4 / Islet-2
Resolution: 1.92→25 Å / Cor.coef. Fo:Fc: 0.952 / Cor.coef. Fo:Fc free: 0.929 / SU B: 4.568 / SU ML: 0.125 / Cross valid method: THROUGHOUT / ESU R: 0.154 / ESU R Free: 0.147 / Details: HYDROGENS HAVE BEEN ADDED IN THE RIDING POSITIONS
Rfactor
Num. reflection
% reflection
Selection details
Rfree
0.24343
1495
5.1 %
RANDOM
Rwork
0.20095
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obs
0.20313
28066
99.42 %
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Solvent computation
Ion probe radii: 0.8 Å / Shrinkage radii: 0.8 Å / VDW probe radii: 1.2 Å