Enzymatic attributes of an l-isoaspartyl methyltransferase from <i>Candida utilis</i> and its role in cell survival.
Banerjee. Shakri S; Dutta. Trina T; Lahiri. Sagar S; Sengupta. Shinjinee S; Gangopadhyay. Anushila A; Kumar Karri. Suresh S; Chakraborty. Sandeep S; Bhattacharya. Debasish D; Ghosh. Anil K AK
Key Findings
- The yeast PCMT enzyme has a Km of 33 µM for isoaspartyl‑containing DSIP, showing it can act on this peptide.
- Boosting PCMT levels in cells improves survival under stressful conditions.
- Higher PCMT activity is associated with increased intracellular ROS and interaction with many housekeeping proteins.
Practical Outcomes
- For biohackers, the study suggests that supporting the body’s natural PCMT activity (e.g., with nutrients that raise SAMe or modest lithium) might aid protein repair and stress resilience. However, the research does not provide specific dosing or protocols for DSIP use, so the immediate actionable steps are limited.
Summary
Scientists studied a repair enzyme from a yeast called Candida utilis. This enzyme, PCMT, can fix damaged proteins that have a specific kind of aging-related change (isoaspartate). They found it works on a peptide called DSIP, helps cells survive stress, and is linked to higher reactive oxygen species inside cells.
Abstract
Spontaneous deamidation and isoaspartate (IsoAsp) formation contributes to aging and reduced longevity in cells. A protein-l-isoaspartate (d-aspartate) O-methyltransferase (PCMT) is responsible for minimizing IsoAsp moieties in most organisms. PCMT was purified in its native form from yeast <i>Candida utilis</i>. The role of the native PCMT in cell survival and protein repair was investigated by manipulating intracellular PCMT levels with Oxidized Adenosine (AdOx) and Lithium Chloride (LiCl). Proteomic Identification of possible cellular targets was carried out using 2-dimensional gel electrophoresis, followed by on-Blot methylation and mass spectrometric analysis. The 25.4 kDa native PCMT from <i>C. utilis</i> was found to have a <i>K<sub>m</sub></i> of 3.5 µM for AdoMet and 33.36 µM for IsoAsp containing Delta Sleep Inducing Peptide (DSIP) at pH 7.0. Native PCMT comprises of 232 amino acids which is coded by a 698 bp long nucleotide sequence. Phylogenetic comparison revealed the PCMT to be related more closely with the prokaryotic homologs. Increase in PCMT levels <i>in vivo</i> correlated with increased cell survival under physiological stresses. PCMT expression was seen to be linked with increased intracellular reactive oxygen species (ROS) concentration. Proteomic identification of possible cellular substrates revealed that PCMT interacts with proteins mainly involved with cellular housekeeping. PCMT effected both functional and structural repair in aged proteins <i>in vitro</i>. Identification of PCMT in unicellular eukaryotes like <i>C. utilis</i> promises to make investigations into its control machinery easier owing to the familiarity and flexibility of the system.
Study Information
pubmed
2015
2015-08-28T00:00:00.000Z
10.1016/j.bbrep.2015.08.015
1
72