High-throughput structure determination of an intrinsically disordered protein using cell-free protein...

Area of Science:

• Structural biology
• Protein science
• Biochemistry

Background:

• Intrinsically disordered proteins (IDPs) lack stable structures, complicating their atomic-level analysis.
• Understanding IDP structure is vital for elucidating their diverse biological roles.
• Identifying structural determinants is key to understanding IDP function and regulation.

Purpose of the Study:

• To develop a rapid method for determining the crystal structures of IDPs.
• To identify the specific residues responsible for stabilizing the structure of an IDP fragment.
• To demonstrate the utility of cell-free protein crystallization for challenging protein targets.

Main Methods:

• Developed a cell-free protein crystallization (CFPC) pipeline for rapid structure analysis.
• Recombined a c-Myc fragment with an in-cell crystallizing protein for expression in a cell-free system.
• Determined crystal structures of the c-Myc fragment using the CFPC method.

Main Results:

• Successfully determined the crystal structure of an 11-residue c-Myc fragment at 1.92 Å resolution.
• Confirmed that the scaffold crystal environment stabilized the c-Myc fragment's α-helical structure, mimicking native interactions.
• Identified two hydrophobic residues as critical determinants for stabilizing the α-helical conformation through analysis of 22 mutants.

Conclusions:

• The CFPC method provides a rapid and effective approach for determining the structures of challenging IDPs.
• The study successfully elucidated key molecular interactions stabilizing IDP structures.
• This technique has significant potential for advancing the structural analysis of IDPs and related proteins.