Crystallization and preliminary X‐ray crystallographic analysis of
Selenocysteine (Sec), the 21st amino acid, is synthesized on its specific tRNA (tRNASec) via a multi‐step process. In bacteria, tRNASec is ligated first with serine by seryl‐tRNA synthetase, which is followed by Ser‐to‐Sec conversion by Sec synthase (SelA). To elucidate its structure and catalytic mechanism, Aquifex aeolicus SelA was crystallized. Although wild‐type SelA crystals diffracted X‐rays poorly (to up to 8 Å resolution), the resolution was improved by introducing a quadruple point mutation targeting the loop regions and by methylating the lysine residues, which yielded 3.9 Å resolution diffraction data from a full‐length SelA crystal. Truncation of the N‐terminal region (ΔN) also improved the resolution. A 3.3 Å resolution data set for phase determination was obtained from a crystal of selenomethionine‐substituted Lys‐methylated SelA‐ΔN.
No Supplementary Data
No Article Media
Document Type: Research Article
Publication date: September 1, 2012