UCT’s Dr Digby Warner.

The University of Cape Town’s Dr Digby Warner spoke on the topic: “Vitamin B12 shot for Mycobacterium Tuberculosis”, at the monthly K-RITH Seminar Series hosted by UKZN’s KwaZulu-Natal Research Institute for Tuberculosis and HIV (K-RITH).

Mycobacterium Tuberculosis (MTB), the bacteria that causes Tuberculosis (TB), is a select group of bacteria which retains the ability for biosynthesising vitamin B12, a chief and intricate natural organometallic cofactor. This vitamin is water-soluble with a significant role in the development of blood for the regular function of the brain and the nervous system.

B12 is important for the body as it is essential for manufacturing red blood cells. A person may become anaemic due to a deficiency of B12. The vitamin is also required for the replication of DNA.

B12 is a vitamin that not many people are aware of and is mostly taken through injections and vitamins, says Digby.

‘The MTB virus predicted a pathway for B12 synthesis and doesn’t have a vitamin B12 transporter. The main question I wanted to answer in my research was: “Can MTB synthesis transport B12”?

‘The MTB genome encodes two B12 riboswitches and three B12-dependent enzymes. Two of these enzymes have been shown to operate in methionine biosynthesis (MetH) and propionate utilisation (MutAB). These observations suggest that MTB has the capacity to regulate core metabolic functions according to B12 availability – whether attained through endogenous synthesis or by acceptance from the host environment,’ said Digby.

‘This therefore implies a role for vitamin B12 in pathogenesis that remains poorly understood.

‘MTB does not synthesise B12, but it can transport B12 as it is able to be incorporated into the TB cell. The B12 vitamin gets pulled into a membrane for being transported and the B12 is handed over from different proteins until it is delivered to the bacteria. TB has the potential to hijack vitamin B12 from its host and TB does not synthesise vitamin B12.

‘The more we do, the less we seem to understand about this organism. B12 appears completely incompatible as it is nature’s most complex vitamin. But is genetically expensive to make B12 and energetically expensive to make the co-factor.’

The K-RITH Seminar Series aims to further scientific integration and collaboration among South African scientists.  K-RITH is based at the Nelson R Mandela School of Medicine campus.