Sequence similarity network analysis, crystallization, and X-ray crystallographic analysis of the lactate metabolism regulator LldR from Pseudomonas aeruginosa

Abstract

Background: The FadR subfamily of regulators plays essential roles in the regulation of diverse metabolic pathways in bacteria. LldR, an FadR-type regulator, regulates lactate utilization in Pseudomonas aeruginosa. Results: Sequence network analysis of the LldR proteins from different bacterial species showed that LldR proteins from Pseudomonas sp. and Escherichia coli were separated into different clusters, suggesting that LldRs are derived from two ancestors that functionally diverged. Then, the recombinant PLldR protein (LldR of P. aeruginosa) was expressed, purified, and crystallized. Preliminary X-ray diffraction analysis of LldR protein crystals was performed. The PLldR crystal diffracted to 2.55 Å resolution and belonged to the trigonal space group P3, with unit-cell parameters a = 68.5 Å, b = 68.5 Å, and c = 237.0 Å. Conclusion: These results will facilitate further understanding of the regulatory mechanism and the adaptation to sensing of both l-lactate and d-lactate of LldR proteins from Pseudomonas sp. in lactate metabolism.