Nascentmeaning The nascent peptide exit tunnel (NPET) is a critical conduit within the ribosome, guiding newly synthesized polypeptide chains from the peptidyl transferase center (PTC) to the cellular environment.作者：MH Kolář·2024·被引用次数：3—The ribosome exit tunnelis formed by RNA and is lined by several ribosomal proteins. A nascent polypeptide engages in a wide variety of ... This tunnel, formed by ribosomal RNA and proteins, is not merely a passive passageway but an active participant in protein synthesis, influencing folding, stability, and even translation regulation作者：N Vázquez-Laslop·2011·被引用次数：74—Specific nascent peptides in the ribosome exit tunnel can elicit translation arrest. Such ribosome stalling is used for regulation of expression of some .... Understanding the dynamics and interactions within the NPET is fundamental to comprehending the intricate process of protein biogenesis and how it can be modulated.
The ribosome exit tunnel is a complex, approximately 100-angstrom-long and 10-20 angstroms wide channel within the large ribosomal subunit.作者：H Ramu·2011·被引用次数：151—The presence of an inducing antibiotic and a specificnascent peptidein theexit tunnelabrogate the ability of the PTC to catalyzepeptide... Its primary role is to facilitate the passage of the nascent polypeptide chain as it emerges from the PTC. The tunnel's internal environment is shaped by ribosomal RNA and specific ribosomal proteins, which contribute to its electrostatic properties and physical dimensions. These structural features are crucial for accommodating the diverse range of polypeptide sequences that traverse it, ensuring that even bulky amino acid residues can navigate the pathwayStructure and Dynamics of Nascent Peptides in the ....
Internally, the tunnel's lining is composed of conserved ribosomal proteins and rRNA, creating a unique microenvironment. This environment can influence the nascent peptide's conformation, promoting early folding events even before the polypeptide chain is fully synthesized. The geometry and electrostatic potential of the tunnel can vary slightly between different organisms and even within different ribosomal subunits, potentially affecting the exit routes and interactions of diverse peptides"Nascent" meaning (in context of nascent peptide ... - YouTube.
The interaction between the nascent peptide and the ribosome exit tunnel is multifaceted and dynamic. As the polypeptide chain elongates, its N-terminus emerges first, followed by subsequent amino acid residues.PubMed Abstract:Interaction between the nascent polypeptide chain and the ribosomal exit tunnelcan modulate the rate of translation and induce ... Early segments of the nascent chain can interact with the tunnel walls, influencing their conformational trajectory. These interactions are not random; specific amino acid sequences within the nascent peptide can engage with the tunnel in ways that affect their own folding and, consequently, the overall protein structure.
Some studies suggest that the nascent polypeptide itself can stabilize the ribosome during translation. The bulky nature of certain amino acid residues at the tunnel entrance can act as a physical block, ensuring elongation continuity and protecting the ribosome. Furthermore, specific nascent peptides have been shown to interact with the tunnel in a manner that can arrest translation. This ribosome stalling mechanism serves as a regulatory element, modulating gene expression by controlling the rate at which specific proteins are synthesized.
Beyond its role as a simple exit route, the ribosome exit tunnel is increasingly recognized for its involvement in regulatory processes. Certain nascent peptides, upon interacting with the tunnel, can trigger translation arrestThree epochs of nascent protein translocation through the .... This phenomenon has been linked to the regulation of downstream gene expression and can be influenced by various cellular signals作者：AK Martínez·2013·被引用次数：47—Interactions of the TnaC nascent peptide with rRNA in the exit tunnelenable the ribosome to respond to free tryptophan.. For instance, the presence of specific molecules or environmental conditions can be sensed by the nascent peptide within the tunnel, leading to a modulation of translation rates.
The TnaC nascent peptide, for example, interacts with rRNA within the exit tunnel, enabling the ribosome to respond to the presence of free tryptophan.Interactions of the TnaC nascent peptide with rRNA in the exit ... This illustrates how the tunnel can act as a sensor, translating extracellular or intracellular signals into changes in protein synthesis作者：PC Burke·2022·被引用次数：32—Nascent peptide in the ribosome exit tunnel... Effect of nascent peptide steric bulk on elongation kinetics in the ribosome exit tunnel.. Such interactions highlight the nascent peptide's ability to engage with the ribosomal machinery, influencing not only its own fate but potentially the broader cellular response.
Several factors can influence how nascent peptides navigate the ribosome exit tunnelThree Stages of Nascent Protein Translocation Through .... The intrinsic properties of the polypeptide chain, such as its amino acid sequence, hydrophobicity, and propensity for secondary structure formation, play a significant role. The steric bulk of amino acid residues can affect elongation kinetics within the tunnel, potentially leading to slower translation rates作者：T Tenson·2002·被引用次数：306—A “universal”tunnel, that is used to export all proteins from the ribosome, should be able to let through many different types ofpeptidesequences..
Moreover, external factors can interact with the nascent peptide within the tunnelNascent polypeptide within the exit tunnel stabilizes .... Antibiotics, for instance, are known to target the ribosome and can exert their effects by interacting with the nascent polypeptide chain in the exit tunnel.Three Stages of Nascent Protein Translocation Through ... These interactions can disrupt protein synthesis, leading to cell death in bacteriaRegulatory Nascent Peptides in the Ribosomal Tunnel. The tunnel's electrostatics also contribute to the interactions, guiding the charged portions of the nascent peptide and influencing its passage.
Research into the nascent peptide exit tunnel continues to uncover its intricate roles in protein synthesis and regulation. Advanced techniques, such as molecular dynamics simulations and cryo-electron microscopy, are providing unprecedented insights into the structural dynamics and interaction mechanisms within the tunnel. Future studies are likely to further elucidate how specific nascent peptide sequences dictate their interactions with the tunnel, how these interactions influence protein folding and function, and how the NPET participates in broader cellular signaling pathways. The growing understanding of the NPET's complexity underscores its significance as a key nexus in the central dogma of molecular biology.2024年4月15日—As the N-terminus of the NP emerges from theexit tunnel, it may interact with translation factors (chaperones, multisubunit complex partners) ...
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