Purification, crystallization and X-ray crystallographic studies on a putative methyltransferase, YtqB, from Bacillus subtilis

Abstract

S-Adenosyl-L-methionine (SAM)-dependent methyltransferases (MTases) catalyze the transfer of a methyl group from a SAM cofactor to specific substrate molecules, including small chemicals, proteins, DNAs and RNAs, and are required for various cellular functions, such as regulation of gene expression and biosynthesis of metabolites. Bacillus subtilis YtqB is a putative SAM-dependent MTase whose biological function has not been characterized. To provide biochemical and structural insights into the role of YtqB in bacteria, the recombinant YtqB protein was overexpressed in the Escherichia coli expression system and purified by chromatographic methods. YtqB crystals were obtained in PEG-containing conditions and diffracted to 1.68 Å resolution. The YtqB crystals belonged to space group P212121, with two molecules in the asymmetric unit.

Keywords: Bacillus subtilis; S-adenosyl-l-methionine; YtqB; methyltransferases.

Figure 1

SDS–PAGE analysis of the purified YtqB protein (lane 2) and protein standards (lane 1; labelled in kDa).

Figure 2

YtqB crystals (∼50 × 50 × 400 µm) obtained in 30% PEG 200, 5% PEG 2000, 0.1 M HEPES pH 7.0.

Figure 3

An X-ray diffraction image of the YtqB crystal shown with a 1.7 Å resolution ring.