Exploring the speed and performance of molecular replacement with AMPLE using QUARK ab initio protein models

Area of Science:

• Structural biology
• Computational biology
• Biophysics

Background:

• Ab initio protein structure prediction is crucial for understanding protein function.
• Molecular replacement is a key technique in determining protein structures.
• Existing methods for generating search models can be time-consuming.

Purpose of the Study:

• To evaluate the effectiveness of AMPLE in generating search models for molecular replacement.
• To assess the complementarity of ab initio models from QUARK and ROSETTA when used with AMPLE.
• To investigate the speed and success rate of AMPLE for in situ structure solution.

Main Methods:

• Ab initio protein structure prediction using QUARK and ROSETTA.
• Clustering and truncation of predicted structures using AMPLE.
• Molecular replacement phasing using Phaser with AMPLE-generated models.
• Evaluation of success rates for all-helical targets.

Main Results:

• AMPLE demonstrates significant complementarity with both QUARK and ROSETTA ab initio models.
• Search models generated by AMPLE successfully solved nearly all tested all-helical targets.
• Phaser produced initial solutions rapidly (within 5 minutes) using AMPLE models.
• AMPLE shows potential for faster and more successful ab initio structure determination.

Conclusions:

• AMPLE is a valuable tool for generating search models for molecular replacement.
• Combining AMPLE with QUARK or ROSETTA enhances ab initio structure prediction capabilities.
• The speed and efficiency of AMPLE improve prospects for in situ structure solution at synchrotrons.