This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Researchers at the Nano Life Science Institute (WPI-NanoLSI) at Kanazawa University have directly visualized how enzymes find and break DNA molecules in real time. Using high-speed atomic force microscopy, the team followed individual enzymes as they moved along DNA and found that they repeatedly returned to vulnerable regions before breaking them apart.
The findings reveal how the structure of DNA influences its vulnerability to enzymatic breakdown. The research was led by Richard Wong and his team: Jingge Yang, Yujia Qiu, Keesiang Lim and Toshio Ando. The work is published in Nature Communications.
DNA is a long molecule that carries the genetic information of living organisms. It is constantly exposed to processes that can damage or break it. Some enzymes—proteins that carry out specific tasks in living organisms—can deliberately break down DNA.
These enzymes, called nucleases, play important roles in maintaining cells and clearing unwanted DNA. One of the best-known of these enzymes is DNase I. It helps remove DNA released from damaged or dying cells.
Problems with this clearance process have been associated with inflammatory and autoimmune diseases. Although scientists know a great deal about the chemistry of DNase I, it has been difficult to see exactly how individual enzyme molecules approach DNA, where they remain and what happens immediately before and after the DNA is cut. The researchers addressed this problem using high-speed atomic force microscopy (HS-AFM), a technique that can record nanoscale changes in biological molecules in liquid without requiring them to be fixed, stained or crystallized.
This allowed the researchers to observe in real time how individual nuclease enzymes interacted with and gradually broke apart DNA. The HS-AFM movies revealed that DNase I did not interact with every part of a DNA molecule in the same way. The enzyme was frequently found near exposed DNA ends and regions where the DNA was curved or locally bent.
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