Lanthanide Biochemistry

Description

Team members & Collaborators

ANNIKA QUIST
UC Berkeley Ph.D Student

Lanthanide Metabolism

We are working to identify peptides produced by Methylobacterium extorquens AM1 that can selectively chemically convert and bind to heavy and light lanthanides. We hope to apply this knowledge to the development of biomining technologies.

Identifying molecules that aid in Ln chemical conversion: Using RNAseq of AM1 grown on Ln halides, oxides, and magnet swarf, we have identified targets that may aid in chemical conversion of lanthanides. We are currently using genetic approaches and ICP-MS of whole cells and supernatants to elucidate the roles these targets play in lanthanide uptake and chemical conversion. In addition, we have identified PQQ as a secreted lanthanide binding factor that is overproduced in a Ln-hyperaccumulating strain. Further research will elucidate how PQQ interacts with insoluble Ln sources and assess the rate at which PQQ, alongside other AM1-produced factors, can convert Ln between varied chemical forms (cation vs. insoluble oxide, phosphate, or magnet swarf).

Identifying molecules that aid in the specific trafficking of heavy and light lanthanides: Using RNAseq of AM1 grown on heavy and light lanthanides, we have identified peptides that may aid selectively in growth on heavy lanthanides. Ongoing investigations are probing the role of these peptides via genetic deletion and overexpression, as well as ICP-MS to identify differences in heavy and light Ln uptake by modified strains. In addition, we have begun to investigate the role of the cofactor PQQ in selectively improving growth rates on heavy but not light lanthanides. Further research will examine the specificity of PQQ for improving heavy Ln utilization by M. extorquens.

Team members & Collaborators

MONICA CESINGER
Postdoctorate Fellow

Characterizing The Novel Mutant Evo-HLn

Many questions remain regarding how lanthanides (Ln) are acquired and used in biology. For most methylotrophic bacteria, the biological use of Ln is restricted to the light Ln species (lanthanum to samarium, atomic numbers 57-62). Understanding how the cell differentiates between light and heavy Ln gives insight into enzyme catalysis, stress homeostasis, and metal biomineralization and compartmentalization.

Our lab has evolved a mutant of Methylobacterium extorquens that is catable of utilizing heavy Ln for growth. The novel mutant evo-HLn, for “evolved for Heavy Lanthanides,” grows robustly on methanol with the heavy Ln gadolinium due to a non-synonymous single nucleotide polymorphism in a cytosolic hybrid histidine kinase/response regulator. We hope to further characterize what components are affected by this major regulatory change and how these changes enable evo-HLn to utilize gadolinium.