SIST: stress-induced structural transitions in superhelical DNA.

Area of Science:

• Genetics and Genomics
• Computational Biology
• Biophysics

Background:

• DNA supercoiling is a critical factor influencing DNA structure and function.
• Alternative DNA structures arise from superhelical stress and are involved in key biological processes like replication and transcription.
• Understanding these sequence-dependent transitions is vital for comprehending DNA dynamics in vivo.

Purpose of the Study:

• To introduce SIST, a software package for analyzing sequence-dependent structural transitions in superhelical DNA.
• To provide tools for studying stress-induced duplex destabilization (SIDD), B-Z transitions, and cruciform extrusion.
• To enable analysis of the competition among these transitions using the DZCBtrans algorithm.

Main Methods:

• SIST employs numerical algorithms based on a statistical mechanical model.
• It calculates the equilibrium probability of transition for each base pair.
• The software extends the stress-induced duplex destabilization (SIDD) method and includes algorithms for B-Z transitions and cruciform extrusion.

Main Results:

• SIST analyzes kilobase-length superhelical DNA molecules.
• It quantifies the likelihood of various structural transitions driven by supercoiling.
• The DZCBtrans algorithm within SIST models the interplay between different transition types.

Conclusions:

• Supercoiling-induced DNA structural transitions are biologically relevant and occur frequently in vivo.
• SIST provides a computational framework to investigate these phenomena.
• The software facilitates the study of DNA structural dynamics and its implications in genetic processes.