Conformational changes induced by K949A mutation in the CRISPR-Cas12a complex drives an effective target-binding...

Area of Science:

• Biochemistry
• Molecular Biology
• Genetics

Background:

• CRISPR/Cas systems offer genome editing potential but face off-target activity challenges.
• Off-target effects are influenced by guide RNA design and Cas nuclease binding.
• Understanding Cas nuclease dynamics is crucial for improving genome editing precision.

Purpose of the Study:

• To compare the conformational dynamics and stability of AsCas12a variants with guide RNA-DNA complexes.
• To investigate the impact of K949A mutation on AsCas12a stability and dynamics.
• To identify critical residues involved in stabilizing Cas variants.

Main Methods:

• Comparative analysis of Wildtype and mutant AsCas12a variants (RR, RVR, RRm, RVRm).
• Molecular dynamics simulations of Cas protein with guide RNA-DNA bound complexes.
• Analysis of conformational dynamics using cross-correlation coefficients and Principal Component Analysis (PCA).

Main Results:

• The K949A mutation significantly increased the cross-correlation between His1167 (NUC domain) and Thr384 (REC II domain).
• Wildtype and RVR variants exhibited extensive flexibility, while mutations led to confined clusters, indicating increased stability.
• The K949A mutation was shown to enhance the stability of PAM variants.

Conclusions:

• The K949A mutation plays a key role in enhancing the stability of AsCas12a PAM variants.
• Specific residues like His1167, Thr384, and Ser959 are predicted to be critical for inducing stability in Cas mutants.
• This research contributes to developing more stable and precise CRISPR/Cas genome editing tools.