N-terminal Modifications
N-terminal Modifications - Related Videos
02:32
Histone Modification
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2020
The histone proteins have a flexible N-terminal tail extending out from the nucleosome. These histone tails are often subjected to post-translational modifications such as acetylation, methylation, phosphorylation, and ubiquitination. Particular combinations of these modifications form “histone codes” that influence the chromatin folding and tissue-specific gene expression. Acetylation The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
01:44
Termination of Translation
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2020
The large ribosomal subunit has several important structures essential to translation. These include the peptidyl transferase center (PTC) - which is the site where the peptide bond is formed - and a large, internal, water-filled tube through which the nascent polypeptide moves. This latter structure is called the Peptide Exit Tunnel, and it begins at the PTC and spans the body of the large ribosomal subunit. During translation, as the nascent polypeptide chain is synthesized, it passes through...
02:25
Spreading of Chromatin Modifications
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2020
The histone proteins in the nucleosomes are post-translationally modified (PTM) to increase or decrease access to DNA. The commonly observed PTMs are methylation, acetylation, phosphorylation, and ubiquitination of lysine amino acids in the histone H3 tail region. These histone modifications have specific meaning for the cell. Hence, they are called "histone code". The protein complex involved in histone modification is termed as "reader-writer" complex. Writers The writer is an enzyme that can...
06:39
Technical Modification of the Terminal Ureter During Total Transperitoneal Laparoscopic Nephroureterectomy for Upper Urinary Tract Urothelial Carcinoma
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Cited by 3 •
2019
Here, we present a protocol to increase the surgical field of view and reduce the difficulty of total transperitoneal laparoscopic nephroureterectomy surgery by precutting the umbilical ligament before treating the terminal ureter.
15:16
Loading Drosophila Nerve Terminals with Calcium Indicators
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Cited by 17 •
2007
Calcium is a ubiquitous messenger in the nervous system, essential for triggering neurotransmitter release and changes in synaptic strength. Here we demonstrate a technique for loading Ca2+-indicators into Drosophila nerve terminals. We also demonstrate fabrication of the required apparatus and emphasize points critical for the technique's success.
FAQs
Removing the initiator methionine changes which residue occupies the mature amino terminus. That newly exposed residue can alter how cellular enzymes recognize the protein and may influence subsequent N-terminal processing or degradation. Consequently, methionine removal is not merely a maturation step; it can affect the protein’s identity, stability, and interactions within the cell.
N-terminal acetylation adds a chemical group to the amino terminus, changing the surface presented to other molecules and cellular recognition systems. This modification can influence protein stability, molecular interactions, and potentially localization. Comparing acetylated and unacetylated forms therefore helps researchers distinguish proteoforms with different cellular behaviors even when their amino acid sequences are otherwise identical.
Lipid attachment changes the chemical properties of the protein’s amino terminus and can affect where the protein is found in the cell. Because localization influences which molecules a protein encounters, this modification may also reshape signaling, trafficking, and molecular interactions. Studying lipid-attached forms can therefore connect an N-terminal change with altered cellular distribution and function.
A regulated processing event can expose a particular residue at the protein’s amino terminus. That exposed residue may be recognized by an N-end rule pathway, linking the protein’s N-terminal state to its degradation. This mechanism allows cells to convert maturation or activation-related processing into a change in protein lifetime, providing a route for controlling protein abundance.
Analytical methods examine the distinct N-terminal states present on proteins, including changes associated with methionine removal, acetylation, lipid attachment, or regulated residue exposure. These measurements help map proteoforms, meaning molecular forms that differ in their modifications or processing. The resulting profiles can reveal how protein maturation and cellular behavior vary across biological conditions.
Protein-engineering approaches can use N-terminal modifications to design proteins with more controlled cellular behavior. Adjusting the amino-terminal state may influence stability, localization, interactions, or susceptibility to degradation. This makes the modifications relevant when the desired engineered outcome depends not only on a protein’s sequence, but also on how cells recognize, traffic, and retain it.