Methionine synthase interreplacement in diatom cultures and communities: Implications for the persistence of B12 use by eukaryotic phytoplankton

• DOI: 10.4319/lo.2013.58.4.1431
• Publication Date: 2016-08-08T23:58:47Z
• Authors: Erin M. Bertrand; Dawn M. Moran; Matthew R. McIlvin; Jeffrey M. Hoffman; Andrew E. Allen; Mak A. Saito
• Keywords: Meth-; Phaeodactylum tricornutum; Methionine synthase

Three proteins related to vitamin B 12 metabolism in diatoms were quantified via selected reaction monitoring mass spectrometry: ‐dependent and ‐independent methionine synthase (MetH, MetE) a acquisition protein (CBA1). ‐mediated interreplacement of MetE MetH metalloenzymes was observed Phaeodactylum tricornutum where abundance highest (0.06 fmol µg −1 protein) under high increased 3.25 low availability. Maximal 60‐fold greater than MetH, consistent with the expected ∼ 50–100‐fold larger turnover number for MetH. expression resulted 30‐fold increase nitrogen 40‐fold zinc allocated activity . CBA1 6‐fold higher low‐B conditions upon resupply starved cultures. While biochemical pathways that supplant requirements exist are utilized by organisms such as land plants, use persists eukaryotic phytoplankton. This study suggests retention utilization phytoplankton results resource conservation abundances also measured diatom communities from McMurdo Sound, verifying both these expressed natural communities. These measurements previous studies suggesting availability influences Antarctic primary productivity. illuminates controls on ‐related proteins, quantitatively assesses metabolic consequences deprivation, demonstrates spectrometry‐based yield insight into functioning marine microbial