Sulfur relay system - Chlamydophila abortus

Ubiquitin and ubiquitin-like proteins (Ubls) are signalling messengers that control many cellular functions, such as cell proliferation, apoptosis, and DNA repair. It is suggested that Ub-protein modification evolved from prokaryotic sulfurtransfer systems. Molybdenum cofactor (Moco) and thiamin are sulfur-containing cofactors whose biosynthesis includes a key sulfur transfer step that uses unique sulfur carrier proteins, MoaD and ThiS. Ubiquitin, MoaD, and ThiS are all structurally related proteins whose C-termini are activated through adenylation by homologous E1-like enzymes. s2T biosynthesis may share similar chemistry with Moco and thiamin synthesis. In Saccharomyces cerevisiae, Urm1 and Uba4 function as part of a ubl protein conjugation system, though they have sequence homology to bacterial sulfur-transfer enzymes and the ability to function in sulfur transfer.

Genetic Information Processing; Folding, sorting and degradation

Chlamydophila abortus [GN:cab]

PMID:19151091

Noma A, Sakaguchi Y, Suzuki T

Mechanistic characterization of the sulfur-relay system for eukaryotic 2-thiouridine biogenesis at tRNA wobble positions.

Nucleic Acids Res 37:1335-52 (2009)

PMID:16859499

Iyer LM, Burroughs AM, Aravind L

The prokaryotic antecedents of the ubiquitin-signaling system and the early evolution of ubiquitin-like beta-grasp domains.

Genome Biol 7:R60 (2006)

PMID:19675644

Schwarz G, Mendel RR, Ribbe MW

Molybdenum cofactors, enzymes and pathways.

Nature 460:839-47 (2009)