peptidyl-methionine modification

Definition

Target type: biologicalprocess

The modification of peptidyl-methionine. [GOC:go_curators]

Peptidyl-methionine modification is a crucial post-translational modification that plays a vital role in protein function and regulation. This process typically occurs after the initial translation of a protein, where a methionine residue is often found at the N-terminus. The modification can occur through various pathways, each with distinct enzymatic machinery and outcomes. Here's a detailed description:

* **N-terminal Methionine Removal:** The most common peptidyl-methionine modification involves the removal of the initiating methionine residue from the N-terminus of a protein. This is catalyzed by methionine aminopeptidases (MetAPs), which are ubiquitous enzymes found in all domains of life. MetAPs recognize and cleave the N-terminal methionine if the following residue is not proline, and if the penultimate residue is not acidic (glutamate or aspartate). This removal is essential for the correct folding and function of many proteins.

* **Formylmethionine Removal:** In bacteria and organelles like mitochondria and chloroplasts, the initiating methionine is formylated, resulting in formylmethionine (fMet). fMet removal is catalyzed by deformylase (DEF), which removes the formyl group from fMet. This step is crucial for protein maturation and interaction with downstream chaperones and protein folding machinery.

* **Methionine Oxidation:** Methionine can be oxidized to methionine sulfoxide (MetO), a reversible modification that can affect protein structure and function. The oxidation can be catalyzed by reactive oxygen species (ROS) like hydrogen peroxide. MetO formation can be detrimental, leading to protein misfolding and aggregation. However, it can also serve as a signaling mechanism, regulating protein activity and stability.

* **Methionine Acetylation:** Methionine acetylation involves the attachment of an acetyl group to the amino group of the methionine residue. This modification can occur at internal methionine residues and is catalyzed by N-terminal acetyltransferases (NATs). Methionine acetylation is implicated in various cellular processes, including protein stability, localization, and interaction with other proteins.

* **Other Modifications:** Other less common modifications of methionine residues include methylation, phosphorylation, and ubiquitination. These modifications can affect protein function and regulation in specific contexts.

In summary, peptidyl-methionine modification is a dynamic process that can significantly influence protein structure, function, and stability. Understanding these modifications is crucial for deciphering the intricate mechanisms of protein biology and for developing strategies to target specific modifications for therapeutic purposes.'
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Proteins (3)

Compounds (20)