Which Enzyme In Bacteria Is Responsible For Transcription?

In bacteria, transcription and translation occur in the cytoplasm, with the enzyme responsible for transcription being RNA polymerase (RNAP). This enzyme is conserved in general architecture and catalytic function across the three domains of life. RNA polymerase is the main transcription enzyme in bacteria, initiating transcription, joining RNA nucleotides together, and terminating transcription. In E. coli, the polymerase is composed of five polypeptide subunits, two of which are identical. Four of these subunits, denoted α, α, β, and β’, comprise the polymerase core enzyme.

The enzyme complex that catalyzes transcription in bacterial cells is either protein-dependent RNA polymerase, DNA-dependent DNA polymerase, or DNA-dependent DNA. RNA polymerase is made up of four subunits, and when a fifth subunit, called the sigma factor (σ-factor), attaches, the polymerase can recognize the sigma factor. RNA polymerase also facilitates opening of the DNA. Bacterial transcription is carried out by a multisubunit RNA polymerase holoenzyme, Eσ, comprised of the core enzyme E and one of several σ specificity subunits.

The correct option is B RNA polymerase, which has the ability to transcribe the DNA as well as opening the DNA double helix. RNA-dependent DNA polymerase, also known as reverse transcriptase (RT), is a DNA polymerase enzyme that transcribes the single RNA strand into DNA.

In conclusion, RNA polymerase is the main transcription enzyme in bacteria, primarily responsible for RNA replication. It initiates transcription, joins RNA nucleotides together, and terminates transcription. The correct option is B RNA polymerase, which can also facilitate the opening of the DNA double helix.

What does transcription in bacteria use?

Bacterial transcription is the process of copying a segment of bacterial DNA into a newly synthesized strand of messenger RNA (mRNA) using the enzyme RNA polymerase. The process involves three main steps: initiation, elongation, and termination, resulting in a complementary strand of mRNA. Many prokaryotic genes occur in operons, which are series of genes that code for the same protein or gene product and are controlled by a single promoter.

Bacterial RNA polymerase is made up of four subunits, with a fifth subunit, called the sigma factor (σ-factor), attached. This allows the polymerase to recognize specific binding sequences in the DNA, called promoters. The binding of the σ-factor to the promoter is the first step in initiation, followed by elongation and the polymerase continuing down the double-stranded DNA until it reaches a termination site.

Transcription is carried out by RNA polymerase but its specificity is controlled by sequence-specific DNA binding proteins called transcription factors. Transcription factors work to recognize specific DNA sequences and based on the cells’ needs, promote or inhibit additional transcription.

Bacterial transcription differs from eukaryotic transcription in several ways. In bacteria, transcription and translation can occur simultaneously in the cytoplasm of the cell, while in eukaryotes, transcription occurs in the nucleus and translation occurs in the cytoplasm. There is only one type of bacterial RNA polymerase, while eukaryotes have three types. Bacteria have a σ-factor that detects and binds to promoter sites, while eukaryotes do not need a σ-factor but instead have transcription factors that allow the recognition and binding of promoter sites.

What are the general transcription factors in bacteria?

In archaea and eukaryotes, transcription initiation requires an RNA polymerase and a set of multiple GTFs to form a transcription preinitiation complex. Transcription initiation by eukaryotic RNA polymerase II involves the following GTFs:

• TFIIA – stabilizes the interaction between the TATA box and TFIID/TATA binding protein (TBP)
• TFIIB – recognizes the B recognition element (BRE) in promoters
• TFIID – binds to TBP and recognizes TBP associated factors (TAFs), also adds promoter selectivity
• TFIIE – attracts and regulates TFIIH
• TFIIF – stabilizes RNA polymerase interaction with TBP and TFIIB
• helps attract TFIIE and TFIIH
• TFIIH – unwinds DNA at the transcription start point, phosphorylates Ser5 of the RNA polymerase CCTD, releases RNA polymerase from the promoter

A sigma factor is a protein needed only for initiation of RNA synthesis in bacteria. Sigma factors provide promoter recognition specificity to the RNA polymerase (RNAP) and contribute to DNA strand separation, then dissociating from the RNA polymerase core enzyme following transcription initiation. The RNA polymerase core associates with the sigma factor to form RNA polymerase holoenzyme. Sigma factor reduces the affinity of RNA polymerase for nonspecific DNA while increasing specificity for promoters, allowing transcription to initiate at correct sites. The core enzyme of RNA polymerase has five subunits ( protein subunits ) (~400 kDa ). Because of the RNA polymerase association with sigma factor, the complete RNA polymerase therefore has 6 subunits: the sigma subunit-in addition to the two alpha (α), one beta (β), one beta prime (β’), and one omega (ω) subunits that make up the core enzyme(~450 kDa). In addition, many bacteria can have multiple alternative σ factors. The level and activity of the alternative σ factors are highly regulated and can vary depending on environmental or developmental signals.

Which enzyme catalyses transcription of RNA in bacteria?

Transcription is the process of RNA synthesis from template DNA, and RNA polymerase (RNAP) is the multisubunit enzyme found in all living organisms, including bacteria, archaea, and eukaryotes. RNAP is the enzyme that transcribes template DNA into RNA, with bacteria and archaea having only one RNAP and eukaryotes having three RNAPs: RNAP I, RNAP II, and RNAP III. Despite differences, RNAPs share many similarities, including three highly conserved subunits.

Bacterial RNAP is the simplest, consisting of five subunits: beta, beta prime, two alphas, and omega. The large beta and beta prime subunits form a claw with the reactive magnesium ion, and a catalytically active site in the center. The initiation of core assembly occurs by dimerizing the N-terminal domain of the alpha subunits, followed by beta and omega, and a flexible linker tethers the C-terminal domains of alphas.

Archaea and eukaryotic core subunits are highly homologous to bacterial RNAP. Bacterial, archaeal, and eukaryotic RNAPs resemble a crab claw with an enzyme active site located at the bottom cleft of the claw. This site contains a catalytic metal magnesium ion, an absolutely conserved motif of NADFDGD, and three invariant residues. The architecture surrounding the cleft is highly conserved among all three domains of life, suggesting that this mechanism of RNA synthesis is conserved from bacteria to humans.

Which enzyme perform transcription?

The enzymes that perform transcription are called RNA polymerases. Like the DNA polymerase that catalyzes DNA replication (discussed in Chapter 5), RNA polymerases catalyze the formation of the phosphodiester bonds that link the nucleotides together to form a linear chain. The RNA polymerase moves stepwise along the DNA, unwinding the DNA helix just ahead of the active site for polymerization to expose a new region of the template strand for complementary base-pairing. In this way, the growing RNA chain is extended by one nucleotide at a time in the 5′-to-3′ direction ( Figure 6-8 ). The substrates are nucleoside triphosphates (ATP, CTP, UTP, and GTP); as for DNA replication, a hydrolysis of high-energy bonds provides the energy needed to drive the reaction forward (see Figure 5-4 ).

Figure 6-8. DNA is transcribed by the enzyme RNA polymerase. The RNA polymerase (pale blue) moves stepwise along the DNA, unwinding the DNA helix at its active site. As it progresses, the polymerase adds nucleotides (here, small “T” shapes) one by (more…)

The almost immediate release of the RNA strand from the DNA as it is synthesized means that many RNA copies can be made from the same gene in a relatively short time, the synthesis of additional RNA molecules being started before the first RNA is completed ( Figure 6-9 ). When RNA polymerase molecules follow hard on each other’s heels in this way, each moving at about 20 nucleotides per second (the speed in eucaryotes), over a thousand transcripts can be synthesized in an hour from a single gene.

Which of the following enzymes is responsible for transcription?

• RNA polymerase is the main enzyme involved in transcription. It generally uses single-strand DNA to synthesize complementary RNA strands.
• In prokaryotes, only a single polymerase is required to bind with the DNA strands,
• The DNA-dependent RNA polymerase also binds to the promoter and catalyzes polymerization in 5′ to 3′ direction on the template strand.
• Once it reaches the terminator sequence, the process generally terminates and the newly synthesized RNA strand is released.

What are the enzymes in bacterial transcription?

Bacterial transcription is carried out by a multisubunit RNA polymerase holoenzyme, Eσ, comprised of the core enzyme E (subunits α2, β, β′ and ω), and one of several σ specificity subunits (a major “housekeeping” sigma factor, such as Escherichia coli σ70, or one of a variable number of alternative sigma factors …

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What is correct for bacterial transcription?

3. Conclusion : – The correct statement regarding bacterial transcription is that transcription and translation take place in the same compartment (the cytoplasm). Therefore, the correct answer is Option 3.

Which enzyme is responsible for taking transcription?

RNA polymerase is an enzyme that is responsible for copying a DNA sequence into an RNA sequence, duyring the process of transcription. As complex molecule composed of protein subunits, RNA polymerase controls the process oftranscription, during which the information stored in a molecule of DNA is copiedinto a new molecule of messenger RNA.

RNA polymerases have been found in all species, but the number and composition of these proteins vary across taxa. For instance, bacteria contain a single type of RNA polymerase, while eukaryotes (multicellular organisms and yeasts) contain three distinct types. In spite of these differences, there are striking similarities among transcriptional mechanisms. For example, all species require a mechanism by which transcription can be regulated in order to achieve spatial and temporal changes in gene expression.

What proteins are involved in bacterial transcription?

Bacteria need to adapt their gene expression in response to environmental signals, causing protein levels to be adjusted according to the needs of the cell. Gene expression regulation also occurs after transcription is initiated, and the importance of these post-transcriptional regulatory processes is highlighted by the weak correlation between RNA and protein abundance. Prokaryotic post-transcriptional regulators, such as small RNAs (sRNAs) and RNA-binding proteins (RBPs), typically modulate RNA decay, translation initiation efficiency, or transcript elongation.

CsrA and Hfq are two well-studied bacterial proteins that regulate the expression of their target genes and how they regulate their own expression or activity in E. coli and other bacteria. Their post-transcriptional function in Escherichia coli was already reported almost 20 years ago. More insight has been gained into the diverse mechanisms these two well-studied proteins use to regulate the expression of their target genes and how they regulate their own expression or activity in E.

Bacterial post-transcriptionally active regulatory proteins typically bind RNA molecules and regulate translation initiation, stability, and transcript elongation of their RNA targets using different regulatory mechanisms. These mechanisms include adaptation of the susceptibility of the target RNAs to RNases, modulation of the accessibility of the RBS of mRNA targets for ribosome binding, acting as a chaperone for the interaction of the RNA target with other effector molecules, and modulation of transcription terminator/antiterminator structure formation.

Which RNA polymerase is responsible for bacterial transcription?

In bacteria, all transcription is performed by a single typeof RNA polymerase. This polymerase contains four catalytic subunits and asingle regulatory subunit known as sigma (s). Interestingly, several distinct sigma factors have been identified, and each ofthese oversees transcription of a unique set of genes. Sigma factors are thusdiscriminatory, as each binds a distinct set of promoter sequences.

A striking example of the specialization of sigma factorsfor different gene promoters is provided by bacterial sporulation in thespecies Bacillus subtilis. This bacterium exists in two states:vegetative (growing) and sporulating. Genes involved in spore formation are notnormally expressed during vegetative growth. Remarkably, expression of a geneencoding a novel sigma factor turns on the first genes for sporulation. Subsequentexpression of different sigma factors then turns on new sets of genes neededlater in the sporulation process (Losick & Stragier, 1992). Eachof these sigma factors recognizes the promoters of the genes in its group, notthose “seen” by other sigma factors. This simple example illustrates howtranscription can be regulated in both cisand trans to cause changes in cellfunction. Therefore, while bacteria accomplish transcription of all genes usinga single kind of RNA polymerase, the use of different sigma factor subunitsprovides an extra level of control.

Eukaryotic cells are more complex than bacteria in many ways, including in terms of transcription. Specifically, in eukaryotes, transcription is achieved by three different types of RNA polymerase (RNA pol I-III). These polymerases differ in the number and type of subunits they contain, as well as the class of RNAs they transcribe; that is, RNA pol I transcribes ribosomal RNAs (rRNAs), RNA pol II transcribes RNAs that will become messenger RNAs (mRNAs) and also small regulatory RNAs, and RNA pol III transcribes small RNAs such as transfer RNAs (tRNAs).

Which of the following enzymes is directly responsible for transcription?

The process of transcription begins when an enzyme called RNA polymerase (RNA pol) attaches to the template DNA strand and begins to catalyze production of complementary RNA. Polymerases are large enzymes composed of approximately a dozen subunits, and when active on DNA, they are also typically complexed with other factors. In many cases, these factors signal which gene is to be transcribed.

Three different types of RNA polymerase exist in eukaryotic cells, whereas bacteria have only one. In eukaryotes, RNA pol I transcribes the genes that encode most of the ribosomal RNAs (rRNAs), and RNA pol III transcribes the genes for one small rRNA, plus the transfer RNAs that play a key role in the translation process, as well as other small regulatory RNA molecules. Thus, it is RNA pol II that transcribes the messenger RNAs, which serve as the templates for production of protein molecules.

The first step in transcription is initiation, when the RNA pol binds to the DNA upstream (5′) of the gene at a specialized sequence called a promoter (Figure 2a). In bacteria, promoters are usually composed of three sequence elements, whereas in eukaryotes, there are as many as seven elements.