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10:21
Expression, Purification, Crystallization, and Enzyme Assays of Fumarylacetoacetate Hydrolase Domain-Containing Proteins
Published on: June 20, 2019
Structural and functional analysis of phosphothreonine-dependent FHA domain interactions
Simon Pennell1, Sarah Westcott, Miguel Ortiz-Lombardía
1Division of Molecular Structure, MRC National Institute for Medical Research, The Ridgeway, London NW71AA, UK. spennel@nimr.mrc.ac.uk
Structure (London, England : 1993)
|December 8, 2010
Summary
FHA domains bind phosphothreonine specifically. This study reveals molecular details of this discrimination, involving hydrogen bonds and van der Waals interactions with a conserved pocket, explaining their role in signal transduction.
Area of Science:
- Molecular Biology
- Biochemistry
- Structural Biology
Background:
- Forkhead-associated (FHA) domains are crucial phospho-dependent binding modules in signal transduction pathways.
- They mediate interactions in Serine/Threonine kinase signaling networks across diverse species.
- The precise molecular basis for FHA domain specificity towards phosphothreonine over phosphoserine remained unclear.
Purpose of the Study:
- To elucidate the molecular mechanisms underlying the binding specificity of FHA domains for phosphothreonine.
- To identify key interactions contributing to the discrimination between phosphothreonine and phosphoserine.
Main Methods:
- Oriented peptide library screening to determine optimal peptide binding sequences for the Rv0020c FHA domain.
- Systematic mutagenic and binding analyses to quantify residue contributions to binding affinity and specificity.
- X-ray crystallography to obtain structures of the FHA domain in complex with phosphopeptides.
- Molecular dynamics simulations to investigate dynamic interactions and stabilization mechanisms.
Main Results:
- Identified an optimal peptide sequence for Rv0020c FHA domain binding.
- Quantified the thermodynamic contributions of conserved residues to binding specificity.
- Structural and simulation data revealed that enhanced phosphothreonine discrimination arises from additional hydrogen-bonding networks.
- Van der Waals interactions of the phosphothreonine γ-methyl group with a conserved pocket stabilize binding.
Conclusions:
- The study provides a detailed molecular explanation for FHA domain specificity towards phosphothreonine.
- Specific hydrogen-bonding networks and van der Waals interactions involving the phosphothreonine methyl group are key.
- These findings enhance our understanding of signal transduction mechanisms mediated by FHA domains.
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