tamra-peptide The elongation of peptide chain is a fundamental stage in protein synthesis, where the polypeptide chain grows by the sequential addition of amino acidsStages of transcription: initiation, elongation & termination (article). This crucial process occurs on the ribosome, guided by the messenger RNA (mRNA) sequence. Understanding the mechanism of peptide chain elongation is key to comprehending how genetic information is translated into functional proteins.
During the elongation phase, the ribosome moves along the mRNA molecule in a stepwise manner, reading codons (three-nucleotide sequences). For each codon, a specific aminoacyl-tRNA (a tRNA molecule carrying a particular amino acid) binds to the ribosome.What Is a Polypeptide Chain? This binding is facilitated by elongation factors, which are proteins that assist in the processAnelongationprotein (EF-Tu) facilitates delivery of charged tRNA to the A site. • After the A site is occupied apeptidebond is formed between the N-..
The elongation cycle involves several key steps:
1. Aminoacyl-tRNA Binding: An aminoacyl-tRNA, matching the next codon on the mRNA, enters the A-site (aminoacyl site) of the ribosome. This step requires energy, typically from GTP hydrolysis, and is mediated by elongation factors (e.g., EF-Tu in bacteria, eEF1A in eukaryotes)A mathematical model for elongation of a peptide chain.
2Stages of transcription: initiation, elongation & termination (article). Peptide Bond Formation: A peptide bond is formed between the amino acid carried by the incoming aminoacyl-tRNA and the growing polypeptide chain attached to the tRNA in the P-site (peptidyl site). This reaction is catalyzed by the peptidyl transferase activity of the ribosome, specifically the ribosomal RNA (rRNA).
3Peptide chain elongation. Translocation: The ribosome moves one codon down the mRNA. This shifts the tRNA that was in the P-site to the E-site (exit site), where it is released, and the tRNA that was in the A-site, now carrying the extended polypeptide chain, moves to the P-site. This translocation step also requires elongation factors (e.g., EF-G in bacteria, eEF2 in eukaryotes) and GTP hydrolysis.
This cycle repeats, with each turn adding one amino acid to the growing polypeptide chain, leading to the stepwise elongation of the polypeptide.
Several molecular components are essential for efficient peptide chain elongation:
* Ribosomes: These are the cellular machinery responsible for protein synthesis, composed of ribosomal RNA (rRNA) and ribosomal proteins.Elongation:New amino acids are brought to the ribosome according to the codon sequence; Translocation: Amino acids are translocated to a growing polypeptide ... They provide the structural framework and catalytic activity for translation.
* mRNA: The messenger RNA molecule carries the genetic code from DNA to the ribosome, dictating the sequence of amino acids to be incorporated.
* tRNA: Transfer RNA molecules act as adaptors, each carrying a specific amino acid and possessing an anticodon that recognizes a complementary codon on the mRNA.
* Aminoacyl-tRNA Synthetases: These enzymes are responsible for accurately attaching the correct amino acid to its corresponding tRNA molecule, a process known as tRNA charging.
* Elongation Factors: These are a class of proteins that play critical roles in promoting the binding of aminoacyl-tRNAs, peptide bond formation, and translocation of the ribosome along the mRNA. In eukaryotes, prominent elongation factors include eEF1 (involved in aminoacyl-tRNA binding) and eEF2 (involved in translocation).作者：A Skoultchi·1970·被引用次数：62—Peptide chain elongation: indications for the binding of an amino acid polymerization factor, guanosine 5'-triphosphate-aminoacyl transfer ribonucleic acid ...
The elongation phase of translation is an energetically demanding process7.4 Translation. The formation of each peptide bond and the translocation steps require the hydrolysis of guanosine triphosphate (GTP), a high-energy molecule2025年8月5日—The rate ofelongation of peptide chainsis found to be a function of the concentration of the amino acid to be bound and the concentration of .... This metabolic energy expenditure ensures the fidelity and efficiency of protein synthesis.
Regulation of peptide chain elongation is crucial for cellular function. Factors such as the availability of amino acids, charged tRNAs, and elongation factors can influence the rate of protein synthesis. Additionally, specific cellular signaling pathways can modulate the activity of elongation factors, allowing the cell to adjust protein production in response to its needs or environmental conditions. For instance, certain factors, like eIF5A, have been shown to facilitate the elongation of specific stretches of amino acids, such as consecutive prolines.
While the fundamental mechanism of peptide chain elongation is conserved across all life forms, there are some differences between prokaryotes and eukaryotes. Eukaryotes typically utilize distinct protein elongation factors, such as eEF-1 and eEF-2, which function in complexes with GTP.作者：A Skoultchi·1969·被引用次数：50—During the elongation phase, theribosome moves along the mRNA(from the 5′ towards the 3′ terminal nucleotide) in steps of 3 nucleotides and attaches one ... The regulation and specific protein factors involved can vary, reflecting the greater complexity of eukaryotic cellular processesPeptide chain elongation.
In summary, the elongation of peptide chain is a dynamic and precisely controlled process that builds proteins based on the genetic instructions encoded in mRNA. It involves the coordinated action of ribosomes, tRNAs, mRNA, and various protein elongation factors, all powered by the hydrolysis of GTP, to ensure the accurate and efficient synthesis of functional polypeptides.
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