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The B12 Claw

January 16, 2013

WHOI scientists recently discovered a previously unknown piece of metabolic machinery that allows algae to grow in the ocean. The cobalamin acquisition protein 1 (CBA1) grabs vitamin B₁₂ out of seawater and brings it into the cell, where the vitamin is used to activate another essential enzyme essential: methionine synthase (MetH). Many algae, as well as humans and other animals require B₁₂, but can’t make it and must either acquire it from the environment or eat food that contains B₁₂. No CBA1 means no B₁₂ which means no growth. To discover CBA1, WHOI biogeochemists Erin Bertrand and Mak Saito used an approach now common in boimedical research, but only recently applied to marine science: proteomics.(Illustration by Amy Carcappa-Qubeck, Woods Hole Oceanographic Institution)