Physical and functional interaction between d-ribokinase and topoisomerase I has opposite effects on their respective activity in Mycobacterium smegmatis and Mycobacterium tuberculosis

► We have characterized the activities of two putative mycobacterial ribokinases. ► The mycobacterial topoisomerase I (TopA) physically interacted with its ribokinase. ► The interaction between the two proteins inhibited the activity of TopA. ► The interaction stimulated ribokinase activity. ► The interaction was conserved in the two mycobacterial species.