Cd2+-induced aggregation of Escherichia coli pyrophosphatase



: Zimenkov YV, Salminen A, Efimova IS, Lahti R, Baykov AA

Publisher: BLACKWELL PUBLISHING LTD

: 2004

: European Journal of Biochemistry

: EUROPEAN JOURNAL OF BIOCHEMISTRY

: EUR J BIOCHEM

: 271

: 14

: 3064

: 3067

: 4

: 0014-2956

DOI: https://doi.org/10.1111/j.1432-1033.2004.04239.x


We report here that Escherichia coli pyrophosphatase aggregates in the presence of millimolar Cd2+. This highly cooperative process was specific to both the metal ion and the protein and could be reversed fully by decreasing the Cd2+ concentration. Aggregation was enhanced by Mg2+, the natural cofactor of pyrophosphatase, and Mn2+. Mutations at the intersubunit metal-binding site had no effect, whereas mutation at Glu139, which is part of the peripheral metal-binding site found in pyrophosphatase crystals near the contact region between two enzyme molecules, suppressed aggregation. These findings indicate that aggregation is affected by Cd2+ binding to the peripheral metal-binding site, probably by strengthening intermolecular Trp149-Trp149' stacking interactions.



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