Rockefeller University Scientists Capture Near-Atomic Visuals of RNA Polymerase During Active Gene Transcription

Rockefeller University study captures RNA polymerase mid-reaction, revealing the water-mediated mechanism that drives gene expression in all forms of life.

By: AXL Media

Published: May 1, 2026, 11:02 AM EDT

Source: Information for this report was sourced from EurekAlert!

Visualizing the Fundamental Chemistry of Life

The process of gene transcription, where RNA polymerase (RNAP) synthesizes RNA from a DNA template, is the essential first step in gene expression for all living organisms. While the general stages of this process have been known for decades, the precise moment of catalysis has remained an elusive "black box" for structural biologists. Recent work from Seth Darst’s Laboratory of Molecular Biophysics at Rockefeller University has successfully captured the enzyme at the transition state just before catalysis begins. By observing RNAP in action, the team has clarified how this complex machine assembles new genetic sequences one building block at a time.

Overcoming the Limitations of Traditional Imaging

For years, scientists relied on X-ray crystallography to approximate the structure of RNAP, but the technique required locking the enzyme into rigid, artificial states that often distorted its natural geometry. The emergence of cryo-electron microscopy (cryo-EM) has allowed the Rockefeller team to image molecules frozen in a near-natural state at near-atomic resolution. According to Andreas Mueller, a research associate involved in the study, this technology enabled the capture of the closest structural snapshot to date of the enzyme’s transition state, resolving the positions of individual ions and water molecules that were previously invisible.

The Role of Water in Catalytic Initiation

A central debate in molecular biology has focused on how RNAP removes a proton to kickstart its core chemical reaction. The new structural models published in Molecular Cell resolve this dispute by revealing a continuous chain of water molecules extending from the enzyme's active site to the surrounding solution. This network serves as a conduit, shuttling protons away to allow the reaction to proceed. This water-mediated mechanism suggests that the enzyme does not act in isolation but relies on a highly coordinated aqueous environment to facilitate the rapid stacking of nucleotides.