Journal
LIMNOLOGY AND OCEANOGRAPHY
Volume 58, Issue 4, Pages 1431-1450Publisher
WILEY
DOI: 10.4319/lo.2013.58.4.1431
Keywords
-
Categories
Funding
- National Science Foundation (NSF) [0732665, 1103503, 0732822]
- NSF Division of Ocean Science [0752291, 0928414, 1031271]
- Gordon and Betty Moore Foundation
- Center for Microbial Oceanography Research and Education
- NSF [2007037200]
- Environmental Protection Agency Science To Achieve Results (EPA-STAR) [F6E720324]
- Directorate For Geosciences
- Division Of Ocean Sciences [1031271, 1260233, 0752291] Funding Source: National Science Foundation
- Directorate For Geosciences
- Division Of Ocean Sciences [0928414] Funding Source: National Science Foundation
- Directorate For Geosciences
- Office of Polar Programs (OPP) [1103503] Funding Source: National Science Foundation
Ask authors/readers for more resources
Three proteins related to vitamin B-12 metabolism in diatoms were quantified via selected reaction monitoring mass spectrometry: B-12-dependent and B-12-independent methionine synthase (MetH, MetE) and a B-12 acquisition protein (CBA1). B-12-mediated interreplacement of MetE and MetH metalloenzymes was observed in Phaeodactylum tricornutum where MetH abundance was highest (0.06 fmol mu g(-1) protein) under high B-12 and MetE abundance increased to 3.25 fmol mu g(-1) protein under low B-12 availability. Maximal MetE abundance was 60-fold greater than MetH, consistent with the expected, similar to 50-100-fold larger turnover number for MetH. MetE expression resulted in 30-fold increase in nitrogen and 40-fold increase in zinc allocated to methionine synthase activity under low B-12. CBA1 abundance was 6-fold higher under low-B-12 conditions and increased upon B-12 resupply to starved cultures. While biochemical pathways that supplant B-12 requirements exist and are utilized by organisms such as land plants, B-12 use persists in eukaryotic phytoplankton. This study suggests that retention of B-12 utilization by phytoplankton results in resource conservation under conditions of high B-12 availability. MetE and MetH abundances were also measured in diatom communities from McMurdo Sound, verifying that both these proteins are expressed in natural communities. These protein measurements are consistent with previous studies suggesting that B-12 availability influences Antarctic primary productivity. This study illuminates controls on expression of B-12-related proteins, quantitatively assesses the metabolic consequences of B-12 deprivation, and demonstrates that mass spectrometry-based protein measurements yield insight into the functioning of marine microbial communities.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available