N-Terminal Protein Binding and Disorder-to-Order Transition by a Synthetic Receptor

Area of Science:

• Biochemistry
• Structural Biology
• Chemical Biology

Background:

• Intrinsically disordered regions (IDRs) pose challenges in structural biology due to their flexibility.
• Macrocycles offer potential for specific molecular recognition and stabilization.

Purpose of the Study:

• To investigate the ability of sulfonato-calix[4]arene (sclx) to capture and structure disordered N-terminal regions of proteins.
• To explore the potential of sclx as a tool for controlling protein conformation.

Main Methods:

• Utilized the trimeric β-propeller Ralstonia solanacearum lectin (RSL) as a scaffold.
• Generated RSL mutants with extended and dynamic N-termini, including Met-Lys motifs and Histone 3 N-terminus.
• Employed X-ray crystallography and NMR spectroscopy to analyze sclx binding and structural effects.

Main Results:

• Demonstrated sclx binding to flexible N-terminal regions of RSL mutants.
• Obtained crystal structures showing sclx recognition and capture of the N-terminal Met-Lys motif.
• Provided crystallographic evidence for sclx encapsulation of N-terminal methionine.

Conclusions:

• Sulfonato-calix[4]arene effectively captures and structures intrinsically disordered N-terminal regions.
• Sclx recognition of specific motifs like Met-Lys drives the capture process.
• Calixarene-mediated capture of IDRs presents potential applications in protein structure and function regulation.