RNA polymerase moves forward along the DNA template one base pair at a time through a process that leverages thermal energy and a mechanism to ensure forward translocation.
Here's a more detailed explanation of how RNA polymerase translocates:
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Translocation: The core of the movement involves RNA polymerase moving one base pair forward along the DNA template strand. This is crucial for adding the next nucleotide to the growing RNA molecule.
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Thermal Energy and Oscillation: The process isn't a smooth, continuous glide. Thermal energy causes the polymerase to oscillate, or move back and forth randomly, along the DNA.
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Directional Bias (Mechanism for Forward Motion): The crucial aspect is how this random, thermal motion is converted into directed forward movement. The polymerase needs a mechanism to favor forward steps over backward steps. The exact mechanism is complex and involves conformational changes within the polymerase that are coupled to nucleotide addition and pyrophosphate release. These changes essentially "ratchet" the polymerase forward.
In simpler terms, imagine RNA polymerase as a tiny machine that's constantly jiggling (due to thermal energy). However, internal mechanisms ensure that each successful "jiggle" is more likely to move it forward than backward, thus progressing it along the DNA.
