Skip to main content

Algae acquire vitamin B12 through a symbiotic relationship with bacteria.

Croft, Martin T., Lawrence, Andrew D., Raux-Deery, Evelyne, Warren, Martin J., Smith, Alison G. (2005) Algae acquire vitamin B12 through a symbiotic relationship with bacteria. Nature, 438 . pp. 90-93. ISSN 0028-0836. E-ISSN 1476-4687. (doi:10.1038/nature04056) (Access to this publication is currently restricted. You may be able to access a copy if URLs are provided) (KAR id:73)

Language: English

Restricted to Repository staff only
Contact us about this Publication
Official URL


Vitamin B12 (cobalamin) was identified nearly 80 years ago as the anti-pernicious anaemia factor in liver, and its importance in human health and disease has resulted in much work on its uptake, cellular transport and utilization. Plants do not contain cobalamin because they have no cobalamin-dependent enzymes. Deficiencies are therefore common in strict vegetarians, and in the elderly, who are susceptible to an autoimmune disorder that prevents its efficient uptake. In contrast, many algae are rich in vitamin B12, with some species, such as Porphyra yezoensis (Nori), containing as much cobalamin as liver. Despite this, the role of the cofactor in algal metabolism remains unknown, as does the source of the vitamin for these organisms. A survey of 326 algal species revealed that 171 species require exogenous vitamin B12 for growth, implying that more than half of the algal kingdom are cobalamin auxotrophs. Here we show that the role of vitamin B12 in algal metabolism is primarily as a cofactor for vitamin B12-dependent methionine synthase, and that cobalamin auxotrophy has arisen numerous times throughout evolution, probably owing to the loss of the vitamin B12-independent form of the enzyme. The source of cobalamin seems to be bacteria, indicating an important and unsuspected symbiosis.

Item Type: Article
DOI/Identification number: 10.1038/nature04056
Subjects: Q Science
Divisions: Faculties > Sciences > School of Biosciences > Protein Science Group
Depositing User: Susan Davies
Date Deposited: 19 Dec 2007 17:53 UTC
Last Modified: 25 Jun 2020 03:00 UTC
Resource URI: (The current URI for this page, for reference purposes)
Raux-Deery, Evelyne:
Warren, Martin J.:
  • Depositors only (login required):


Downloads per month over past year