8UZW

Selenocysteine synthase- SelA

Summary for 8UZW

• Entry DOI: 10.2210/pdb8uzw/pdb
• EMDB information: 42845
• Descriptor: L-seryl-tRNA(Sec) selenium transferase (1 entity in total)
• Functional Keywords: selenocysteine, trnasec, sec-synthase, rna binding protein
• Biological source: Escherichia coli
• Total number of polymer chains: 10
• Total formula weight: 508951.72

Authors

Balasco Serrao, V.H.,Minari, K.,Pereira, H.M.,Thiemann, O.H. (deposition date: 2023-11-16, release date: 2024-04-24, Last modification date: 2024-06-26)

Primary citation

Balasco Serrao, V.H.,Minari, K.,Pereira, H.D.,Thiemann, O.H.
Bacterial selenocysteine synthase structure revealed by single-particle cryoEM.
Curr Res Struct Biol, 7:100143-100143, 2024

PubMed Abstract: The 21st amino acid, selenocysteine (Sec), is synthesized on its dedicated transfer RNA (tRNA). In bacteria, Sec is synthesized from Ser-tRNA by Selenocysteine Synthase (SelA), which is a pivotal enzyme in the biosynthesis of Sec. The structural characterization of bacterial SelA is of paramount importance to decipher its catalytic mechanism and its role in the regulation of the Sec-synthesis pathway. Here, we present a comprehensive single-particle cryo-electron microscopy (SPA cryoEM) structure of the bacterial SelA with an overall resolution of 2.69 Å. Using recombinant SelA, we purified and prepared samples for single-particle cryoEM. The structural insights from SelA, combined with previous and knowledge, underscore the indispensable role of decamerization in SelA's function. Moreover, our structural analysis corroborates previous results that show that SelA adopts a pentamer of dimers configuration, and the active site architecture, substrate binding pocket, and key K295 catalytic residue are identified and described in detail. The differences in protein architecture and substrate coordination between the bacterial enzyme and its counterparts offer compelling structural evidence supporting the independent molecular evolution of the bacterial and archaea/eukarya Ser-Sec biosynthesis present in the natural world.

PubMed: 38681238
DOI: 10.1016/j.crstbi.2024.100143

Experimental method

ELECTRON MICROSCOPY (2.69 Å)