Related Experiment Video
Updated: Aug 2, 2026
07:44
High-throughput Purification of Affinity-tagged Recombinant Proteins
Published on: August 26, 2012
Structure of a ternary transcription activation complex
Deepti Jain1, Bryce E Nickels, Li Sun
1The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
Molecular Cell
|January 21, 2004
Summary
Bacteriophage lambda cI protein and sigma(4) interact minimally to activate transcription. This cooperative binding stabilizes protein-DNA interactions, influencing transcription initiation.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- Bacteriophage lambda cI protein activates transcription via DNA operator binding and sigma subunit interaction.
- RNA polymerase sigma subunit domain 4 (sigma(4)) is a key interaction partner for transcriptional activators.
Purpose of the Study:
- To determine the high-resolution crystal structure of the lambdacI/sigma(4)/DNA ternary complex.
- To elucidate the molecular mechanism of transcriptional activation by lambdacI.
Main Methods:
- X-ray crystallography at 2.3 A resolution.
- Structural analysis of protein-protein and protein-DNA interactions.
Main Results:
- The crystal structure revealed no significant conformational changes in lambdacI or sigma(4).
- The proteins interact via a small interface (at most 6 amino acid residues).
- Protein-protein interactions stabilize the binding of both lambdacI and sigma(4) to the DNA.
Conclusions:
- Transcriptional activators can function through simple cooperative binding mechanisms.
- The interaction stabilizes protein-DNA binding, impacting transcription initiation.
- This study provides structural insights into the cooperative binding mechanism of transcriptional activators.
More Related Videos
Related Concept Videos
02:36RNA Polymerase II Accessory Proteins
Proteins that regulate transcription can do so either via direct contact with RNA Polymerase or through indirect interactions facilitated by adaptors, mediators, histone-modifying proteins, and nucleosome remodelers. Direct interactions to activate transcription is seen in bacteria as well as in some eukaryotic genes. In these cases, upstream activation sequences are adjacent to the promoters, and the activator proteins interact directly with the transcriptional machinery. For example, in...
02:04Co-activators and Co-repressors
Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...
02:42Eukaryotic Transcription Activators
Transcription activators are proteins that promote the transcription of genes from DNA to RNA. In most cases, these proteins contain two separate domains ‒ a domain that binds to DNA and a domain for activating transcription; however, in some cases, a single domain is responsible for both binding and activation of transcription, as seen in the glucocorticoid receptor and MyoD.
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These domains are...
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These domains are...
01:30General Transcription Factors
Tissue-specific transcription factors contribute to diverse cellular functions in mammals. For example, the gene for beta globin, a major component of hemoglobin, is present in all cells of the body. However, it is only expressed in red blood cells because the transcription factors that can bind to the promoter sequences of the beta globin gene are only expressed in these cells. Tissue-specific transcription factors also ensure that mutations in these factors may impair only the function of...
02:36RNA Polymerase II Accessory Proteins
Proteins that regulate transcription can do so either via direct contact with RNA Polymerase or through indirect interactions facilitated by adaptors, mediators, histone-modifying proteins, and nucleosome remodelers. Direct interactions to activate transcription is seen in bacteria as well as in some eukaryotic genes. In these cases, upstream activation sequences are adjacent to the promoters, and the activator proteins interact directly with the transcriptional machinery. For example, in...
02:04Co-activators and Co-repressors
Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...