DNA-directed RNA polymerase complex

Definition

Target type: cellularcomponent

A protein complex that possesses DNA-directed RNA polymerase activity. [GOC:krc]

The DNA-directed RNA polymerase complex is a molecular machine responsible for transcribing DNA into RNA. It is composed of multiple subunits that work together to perform this crucial function.

The core enzyme of bacterial RNA polymerase consists of five subunits: two alpha subunits (α), one beta subunit (β), one beta prime subunit (β'), and one omega subunit (ω). These subunits form a complex that binds to DNA and facilitates the unwinding and separation of the DNA strands.

The alpha subunits are involved in the assembly of the core enzyme, promoter recognition, and interactions with regulatory proteins. The beta subunit contains the active site for RNA synthesis and plays a critical role in the catalytic process. The beta prime subunit provides structural support and participates in DNA binding. The omega subunit stabilizes the core enzyme and promotes its assembly.

In addition to the core enzyme, RNA polymerase can associate with a sigma factor (σ). Sigma factors are responsible for recognizing and binding to specific DNA sequences called promoters. They are essential for the initiation of transcription. Different sigma factors can recognize different promoters, allowing the cell to regulate the expression of different genes under specific conditions.

The DNA-directed RNA polymerase complex undergoes conformational changes during the transcription cycle. These changes are essential for the accurate initiation, elongation, and termination of RNA synthesis. The complex undergoes a series of steps including promoter recognition, initiation, elongation, termination, and recycling.

The cellular component of the DNA-directed RNA polymerase complex is the nucleoid, which is the region within the bacterial cytoplasm that houses the bacterial chromosome. The complex is located within the nucleoid and interacts with DNA to perform its function.

In summary, the DNA-directed RNA polymerase complex is a complex molecular machine composed of multiple subunits that work together to transcribe DNA into RNA. It is located within the nucleoid and plays a crucial role in gene expression and cellular function.'
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Proteins (4)

Compounds (2)