UBA4 (Adenylyltransferase and sulfurtransferase UBA4)

FEATURES

DESCRIPTION

Also known as UBA4_PICST, UBA4. Plays a central role in 2-thiolation of mcm(5)S(2)U at tRNA wobble positions of cytosolic tRNA(Lys), tRNA(Glu) and tRNA(Gln). Acts by mediating the C-terminal thiocarboxylation of sulfur carrier URM1. Its N-terminus first activates URM1 as acyl-adenylate (-COAMP), then the persulfide sulfur on the catalytic cysteine is transferred to URM1 to form thiocarboxylation (-COSH) of its C-terminus. The reaction probably involves hydrogen sulfide that is generated from the persulfide intermediate and that acts as nucleophile towards URM1. Subsequently, a transient disulfide bond is formed. Does not use thiosulfate as sulfur donor; NFS1 probably acting as a sulfur donor for thiocarboxylation reactions. Prior mcm(5) tRNA modification by the elongator complex is required for 2-thiolation. May also be involved in protein urmylation.

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EXTERNAL LINKS

UBA4

Adenylyltransferase and sulfurtransferase UBA4

LIGANDABILITY MUTATIONS

UBA4

Molecular Synopsis