A study of Rose Bengal against a 2-keto-3-deoxy-d-manno-octulosonate cytidylyltransferase as an antibiotic candidate

Abstract

Frequent occurrences of multi-drug resistance of pathogenic Gram-negative bacteria threaten human beings. The CMP-2-keto-3-deoxy-d-manno-octulosonic acid biosynthesis pathway is one of the new targets for antibiotic design. 2-Keto-3-deoxy-d-manno-octulosonate cytidylyltransferase (KdsB) is the key enzyme in this pathway. KdsB proteins from Burkholderia pseudomallei (Bp), B. thailandensis (Bt), Pseudomonas aeruginosa (Pa), and Chlamydia psittaci (Cp) have been assayed to find inhibitors. Interestingly, Rose Bengal (4,5,6,7-tetrachloro-2′,4′,5′,7′-tetraiodofluorescein) was turned out to be an inhibitor of three KdsBs (BpKdsB, BtKdsB, and PaKdsB) with promising IC₅₀ values and increased thermostability. The inhibitory enzyme kinetics of Rose Bengal revealed that it is competitive with 2-keto-3-deoxy-manno-octulosonic acid (KDO) but non-competitive against cytidine 5′-triphosphate (CTP). Induced-fit docking analysis of PaKdsB revealed that Arg160 and Arg185 together with other interactions in the substrate binding site seemed to play an important role in binding with Rose Bengal. We suggest that Rose Bengal can be used as the scaffold to develop potential antibiotics.

Keywords:

• CMP-2-keto-3-deoxy-d-manno-octulosonic acid biosynthesis pathway
• 2-keto-3-deoxy-d-manno-octulosonate cytidylyltransferase (KdsB)
• melioidosis
• multi-drug resistance
• Rose Bengal

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Basic Science Research Programs, 2018R1D1A1B07050781 to DHS and 2018R1D1A1B07050942 to M-SK, funded by the National Research Foundation of Korea grant granted by the Ministry of Education, Science and Technology, Republic of Korea (MEST).