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Related Experiment Video

Updated: Nov 19, 2025

In Vitro Analysis of E3 Ubiquitin Ligase Function

In Vitro Analysis of E3 Ubiquitin Ligase Function

Published on: May 14, 2021

Urm1: A Non-Canonical UBL.

Martin Termathe¹, Sebastian A Leidel²

¹Institute of Biochemistry, Protein Biochemistry and Photobiocatalysis, University of Greifswald, Felix-Hausdorff-Strasse 4, 17489 Greifswald, Germany.

|January 27, 2021

Summary

Ubiquitin related modifier 1 (Urm1) protein modifies tRNA, optimizing translation across all life. Its unique dual function makes it a model for studying protein conjugation and sulfur carrier systems.

Keywords:

2-thiolation non-canonical UBL rhodanese sulfur-carrier protein tRNA modification thiocarboxylate ubiquitin-like protein

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Last Updated: Nov 19, 2025

In Vitro Analysis of E3 Ubiquitin Ligase Function

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Published on: June 17, 2020

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Published on: July 25, 2019

Area of Science:

Biochemistry
Molecular Biology
Evolutionary Biology

Background:

Urm1 (ubiquitin related modifier 1) is a ubiquitin-like protein (UBL) with characteristics of bacterial sulfur-carrier proteins (SCP).
Urm1 modifies tRNA, a non-canonical function crucial for optimizing translation.
The activating enzyme Uba4 possesses both E1-like and rhodanese homology domains.

Purpose of the Study:

To summarize recent findings on Urm1's unique features.
To highlight Urm1's position at the intersection of UBL and SCP.
To establish Urm1 as a model for studying the evolution of protein conjugation and sulfur-carrier systems.

Main Methods:

Review of existing literature on Urm1 function and evolution.
Analysis of Urm1's dual characteristics as a UBL and SCP.
Investigation of Urm1's role in tRNA modification and translation.

Main Results:

Urm1's sulfurtransferase domain catalyzes thiocarboxylation, essential for mcm5s2U modification in tRNA.
This modification is conserved across all domains of life and optimizes translation.
Urm1 absence in yeast leads to stress sensitivity, linked to neurological defects in higher organisms.

Conclusions:

Urm1 represents a molecular fossil bridging UBLs and SCPs.
Its unique structure and function offer insights into the evolution of protein modification and sulfur metabolism.
Urm1 is a valuable model for understanding fundamental biological processes and their links to disease.