Solution structure of a functional biomimetic and mechanistic implications for nickel superoxide dismutases.
The nickel complex of a synthetic nonapeptide (HCDLPCFVY-NH2) is capable of catalytically disproportionating O2(.-) and is thus a functional biomimetic for nickel superoxide dismutases. This represents a simplification as compared to a NiSOD "maquette" that is based on a dodecapeptide that was recently reported [Inorg. Chem. 2006, 45, 2358]. The 3D solution structure reveals that the first six residues form a stable macrocyclic structure with a preformed binding site for Ni(II). Proline 5 exhibits a trans peptide linkage in the biomimetic and a cis conformation in NiSOD enzymes. DFT calculations reveal the source of this preference. Mechanistic consequences for the mode of action (identity of the fifth ligand) are discussed. The SOD activity is compared to enzymatic systems, and selected modifications allowed the biomimetic to be reduced to a functional minimal motif of only six amino acids (ACAAPC-NH2).
Schmidt
Matthias
M
Leibniz-Institut für Altersforschung, Beutenbergstrasse 11, 07745 Jena, Germany.
Zahn
Stefan
S
Carella
Michela
M
Ohlenschläger
Oliver
O
Görlach
Matthias
M
Kothe
Erika
E
Weston
James
J
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D040761:Biomimetic Materials / Q000737:chemistry* / Q000378:metabolism*; D009532:Nickel / Q000378:metabolism*; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism; D011392:Proline / Q000737:chemistry; D011487:Protein Conformation; D011789:Quantum Theory; D012996:Solutions; D013302:Streptomyces / Q000201:enzymology*; D013482:Superoxide Dismutase / Q000737:chemistry* / Q000378:metabolism*
D009842:Oligopeptides; D012996:Solutions; D009532:Nickel; D011392:Proline; D013482:Superoxide Dismutase