PXD031524

PXD031524 is an original dataset announced via ProteomeXchange.

Title	Flexible B12 ecophysiology of Phaeocystis antarctica due to a B12-independent methionine synthase fusion protein with widespread homologues
Description	Coastal Antarctic marine ecosystems play an important role in carbon cycling due to their highly productive seasonal phytoplankton blooms. Southern Ocean microbes are primarily limited by light and iron (Fe) and can be co-limited by cobalamin (vitamin B12 ). Micronutrient limitation is a key driver of ecosystem dynamics and influences the composition of blooms, which are often dominated by either diatoms or the haptophyte Phaeocystis antarctica, each with varied impacts on carbon cycling. However, the vitamin requirements and ecophysiology of the keystone species P. antarctica remains poorly characterized. Using cultures, physiological analysis, and comparative ’omics we examined the response of P. antarctica to a matrix of Fe-B12 conditions. We show that P. antarctica is not auxotrophic for B12 , as previously suggested, and report new mechanistic insights of its B12 response in cultures of predominantly solitary and colonial cells. Proteomics coupled with proteogenomics detected a B12 -independent methionine synthase fusion protein (MetE-fusion) that is expressed under vitamin limitation and is interreplaced with the B12 -dependent isoform (MetH) in replete conditions. Database searches returned homologs of the MetE-fusion protein in multiple Phaeocystis species and in a wide range of marine microbes, including other photosynthetic eukaryotes with polymorphic life cycles and also bacterioplankton. Furthermore, MetE-fusion homologs were found to be expressed in metaproteomic and metatranscriptomic field samples in polar and more geographically widespread regions. As climate change impacts micronutrient availability in the coastal Southern Ocean, our finding that P. antarctica has a flexible B12 metabolism has implications for its relative fitness compared to B12 -auxotrophic diatoms.
HostingRepository	PRIDE
AnnounceDate	2023-02-27
AnnouncementXML	Submission_2023-02-27_09:16:32.528.xml
DigitalObjectIdentifier	https://dx.doi.org/10.6019/PXD031524
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Supported dataset by repository
PrimarySubmitter	MatthewMcIlvin
SpeciesList	scientific name: Phaeocystis antarctica; NCBI TaxID: 33657;
ModificationList	acetylated residue; iodoacetamide derivatized residue
Instrument	Q Exactive

Revision	Datetime	Status	ChangeLog Entry
0	2022-02-09 05:09:01	ID requested
⏵ 1	2023-02-27 09:16:32	announced

10.6019/PXD031524;

submitter keyword: LC-MSMS, vitamin B12,Phaeocystis antarctica, methionine synthase fusion protein

MakSaito
contact affiliation	Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA
contact email	msaito@whoi.edu
lab head
MatthewMcIlvin
contact affiliation	Woods Hole Oceanographic Inst.
contact email	mmcilvin@whoi.edu
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD031524
     1. Label: PRIDE project
     2. Name: Flexible B12 ecophysiology of Phaeocystis antarctica due to a B12-independent methionine synthase fusion protein with widespread homologues