Crystal structure of a calcium(II)-pyrroloquinoline quinone (PQQ) complex outside a protein environment.

ABSTRACT: Pyrroloquinoline quinone (PQQ) is an important cofactor of calcium- and lanthanide-dependent alcohol dehydrogenases, and has been known for over 30 years. Crystal structures of Ca-MDH enzymes (MDH is methanol dehydrogenase) have been known for some time; however, crystal structures of PQQ with biorelevant metal ions have been lacking in the literature for decades. We report here the first crystal structure analysis of a Ca-PQQ complex outside the protein environment, namely, poly[[undecaaquabis(?-4,5-dioxo-4,5-dihydro-1H-pyrrolo[2,3-f]quinoline-2,7,9-tricarboxylato)tricalcium(II)] dihydrate], {[Ca₃(C₁₄H₃N₂O₈)₂(H₂O)₁₁]·2H₂O}_n. The complex crystallized as Ca₃PQQ₂·13H₂O with Ca²⁺ in three different positions and PQQ^3-, including an extensive hydrogen-bond network. Similarities and differences to the recently reported structure with biorelevant europium (Eu₂PQQ₂) are discussed.

SUBMITTER: Lumpe H 

PROVIDER: S-EPMC7716187 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature