Expression, purification, crystallization and preliminary X-ray crystallographic analysis of the l,d-transpeptidase Ldt_Mt1 from Mycobacterium tuberculosis

In this study, the l,d-transpeptidase Ldt_Mt1 was cloned, expressed and crystallized. Multiwavelength anomalous dispersion experiments have been carried out to obtain experimental phases using data at 2.9 Å resolution from a selenomethionine derivative. Mycobacterium tuberculosis is capable of adapting to prolonged periods of dormancy, a state which is resistant to killing by antimycobacterial agents. The l,d-transpeptidation reaction catalysed by the l,d-transpeptidase Ldt_Mt1 is likely to play an essential role in the adaptation of M. tuberculosis to its dormant state. Ldt_Mt1 has been successfully crystallized using vapour-diffusion methods. The crystals of this protein belonged to space group P6₅22, with unit-cell parameters a = 57.25, b = 57.25, c = 257.96 Å, α = 90, β = 90, γ = 120°. Diffraction data have also been collected from a selenomethionine derivative to 2.9 Å resolution. Model building using the phases derived from the multiwavelength anomalous dispersion experiment is in progress