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Crystal structure of a calcium(II)–pyrroloquinoline quinone (PQQ) complex outside a protein environment
Author(s) -
Lumpe Henning,
Mayer Peter,
Daumann Lena J.
Publication year - 2020
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229620014278
Subject(s) - pyrroloquinoline quinone , methanol dehydrogenase , cofactor , chemistry , crystal structure , hydrogen bond , methanol , stereochemistry , quinone , calcium , enzyme , alcohol dehydrogenase , crystallography , molecule , biochemistry , organic chemistry
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(μ‐4,5‐dioxo‐4,5‐dihydro‐1 H ‐pyrrolo[2,3‐ f ]quinoline‐2,7,9‐tricarboxylato)tricalcium(II)] dihydrate], {[Ca 3 (C 14 H 3 N 2 O 8 ) 2 (H 2 O) 11 ]·2H 2 O} n . The complex crystallized as Ca 3 PQQ 2 ·13H 2 O with Ca 2+ in three different positions and PQQ 3− , including an extensive hydrogen‐bond network. Similarities and differences to the recently reported structure with biorelevant europium (Eu 2 PQQ 2 ) are discussed.