Lanmodulin: A Highly Selective Lanthanide-Binding Protein from a Lanthanide-Utilizing Bacterium

Joseph Alfred Cotruvo, Jr., Emily R. Featherston, Joseph A. Mattocks, Jackson V. Ho, Tatiana Nikolaevna Laremore

Research output: Contribution to journalArticlepeer-review

50 Scopus citations

Abstract

Lanthanides (Lns) have been shown recently to be essential cofactors in certain enzymes in methylotrophic bacteria. Here we identify in the model methylotroph, Methylobacterium extorquens, a highly selective LnIII-binding protein, which we name lanmodulin (LanM). LanM possesses four metal-binding EF hand motifs, commonly associated with CaII-binding proteins. In contrast to other EF hand-containing proteins, however, LanM undergoes a large conformational change from a largely disordered state to a compact, ordered state in response to picomolar concentrations of all LnIII (Ln = La-Lu, Y), whereas it only responds to CaII at near-millimolar concentrations. Mutagenesis of conserved proline residues present in LanM's EF hands, not encountered in CaII-binding EF hands, to alanine pushes CaII responsiveness into the micromolar concentration range while retaining picomolar LnIII affinity, suggesting that these unique proline residues play a key role in ensuring metal selectivity in vivo. Identification and characterization of LanM provides insights into how biology selectively recognizes low-abundance LnIII over higher-abundance CaII, pointing toward biotechnologies for detecting, sequestering, and separating these technologically important elements.

Original languageEnglish (US)
Pages (from-to)15056-15061
Number of pages6
JournalJournal of the American Chemical Society
Volume140
Issue number44
DOIs
StatePublished - Nov 7 2018

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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