Functional characterisation of substrate-binding proteins to address nutrient uptake in marine picocyanobacteria

Benjamin A. Ford, Geraldine J. Sullivan, Lisa Moore, Deepa Varkey, Hannah Zhu, Martin Ostrowski, Bridget C. Mabbutt, Ian T. Paulsen, Bhumika S. Shah*

*Corresponding author for this work

    Research output: Contribution to journalReview articlepeer-review

    4 Citations (Scopus)
    36 Downloads (Pure)


    Marine cyanobacteria are key primary producers, contributing significantly to the microbial food web and biogeochemical cycles by releasing and importing many essential nutrients cycled through the environment. A subgroup of these, the picocyanobacteria (Synechococcus and Prochlorococcus), have colonised almost all marine ecosystems, covering a range of distinct light and temperature conditions, and nutrient profiles. The intra-clade diversities displayed by this monophyletic branch of cyanobacteria is indicative of their success across a broad range of environments. Part of this diversity is due to nutrient acquisition mechanisms, such as the use of high-affinity ATP-binding cassette (ABC) transporters to competitively acquire nutrients, particularly in oligotrophic (nutrient scarce) marine environments. The specificity of nutrient uptake in ABC transporters is primarily determined by the peripheral substrate-binding protein (SBP), a receptor protein that mediates ligand recognition and initiates translocation into the cell. The recent availability of large numbers of sequenced picocyanobacterial genomes indicates both Synechococcus and Prochlorococcus apportion >50% of their transport capacity to ABC transport systems. However, the low degree of sequence homology among the SBP family limits the reliability of functional assignments using sequence annotation and prediction tools. This review highlights the use of known SBP structural representatives for the uptake of key nutrient classes by cyanobacteria to compare with predicted SBP functionalities within sequenced marine picocyanobacteria genomes. This review shows the broad range of conserved biochemical functions of picocyanobacteria and the range of novel and hypothetical ABC transport systems that require further functional characterisation.
    Original languageEnglish
    Pages (from-to)2465-2481
    Number of pages17
    JournalBiochemical Society Transactions
    Issue number6
    Early online date9 Dec 2021
    Publication statusPublished - Dec 2021

    Bibliographical note

    Copyright the Author(s) 2021. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.


    • ABC transport proteins
    • cyanobacteria
    • nutrient uptake
    • Prochlorococcus
    • substrate binding proteins
    • Synechococcus


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