Dataset Information

Molecular characterization of the eukaryotic Uba4/Urm1 system

ABSTRACT: Ubiquitin-like protein activator 4 (Uba4) is required for the thiolation of uridine bases in eukaryotic transfer RNA. Uba4 catalyzes the sequential adenylation and thiocarboxylation of the C-terminus of Ubiquitin related modifier 1 (Urm1), acting as a hybrid between an E1-like activating enzyme and a sulfur-transferase. Structural and mechanistic details of the eukaryotic Uba4 protein and its respective reaction intermediates remained elusive. Here, we report the high-resolution crystal structures of full length Uba4 from Chaetomium thermophilum and its heterodimeric complex with Urm1. The structures show, how the aligned adenylation and rhodanese-like domains of Uba4 orchestrate substrate binding and specifically recognize and activate Urm1 at its C-terminus. We use complementary assays in vitro and in vivo to functionally validate all our structural findings. Furthermore, we uncover that under oxidative stress the specific relay of catalytic cysteines, similar to E1-E2 cascades, protects Uba4 from covalent conjugation by its own product, namely thiocarboxylated Urm1.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Chaetomium Thermophilum

SUBMITTER: Urszula Jankowska

LAB HEAD: Urszula Jankowska

PROVIDER: PXD015802 | Pride | 2020-07-14

REPOSITORIES: Pride

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Publications

Molecular basis for the bifunctional Uba4-Urm1 sulfur-relay system in tRNA thiolation and ubiquitin-like conjugation.

Pabis Marta M Termathe Martin M Ravichandran Keerthiraju E KE Kienast Sandra D SD Krutyhołowa Rościsław R Sokołowski Mikołaj M Jankowska Urszula U Grudnik Przemysław P Leidel Sebastian A SA Glatt Sebastian S

The EMBO journal 20200909 19

The chemical modification of tRNA bases by sulfur is crucial to tune translation and to optimize protein synthesis. In eukaryotes, the ubiquitin-related modifier 1 (Urm1) pathway is responsible for the synthesis of 2-thiolated wobble uridine (U<sub>34</sub> ). During the key step of the modification cascade, the E1-like activating enzyme ubiquitin-like protein activator 4 (Uba4) first adenylates and thiocarboxylates the C-terminus of its substrate Urm1. Subsequently, activated thiocarboxylated U ...[more]

PMID: 32901956

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			Action	DRS
	Uba4C202K_A1.msf	Msf
	Uba4C202K_A1.raw	Raw
	Uba4C202K_A2.msf	Msf
	Uba4C202K_A2.raw	Raw
	Uba4C202S_B1.msf	Msf