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Structural implications for heavy metal‐induced reversible assembly and aggregation of a protein: the case of Pyrococcus horikoshii CutA 1

2003; Wiley; Volume: 556; Issue: 1-3 Linguagem: Inglês

10.1016/s0014-5793(03)01402-9

1873-3468

Yoshikazu Tanaka, Kouhei Tsumoto, Takeshi Nakanishi, Y. Yasutake, Naoki Sakai, Min Yao, Isao Tanaka, Izumi Kumagai,

Enzyme Structure and Function

CutA is a small protein that appears to be involved in the mechanism of divalent metal cation tolerance in microorganisms. Here we report the crystal structure of Pyrococcus horikoshii CutA ( Pho CutA), with and without Cu 2+ , and its metal‐binding properties. Crystallographic analyses revealed that Pho CutA forms a stable trimeric structure with intertwined antiparallel β‐strands. The crystal structure of the Cu 2+ – Pho CutA complex shows that the Cu 2+ is located at a trimer–trimer interface and is recognized by the side chains of one Asp 48 from each trimer. In an in vitro experiment, Pho CutA bound to several heavy metals, most of which led to reversible aggregation of the protein; i.e. the aggregates could be completely solubilized by addition of ethylenediamine tetraacetic acid (EDTA) or dialysis against metal free buffer. Substitution of Asp 48 with Ala led to a decrease in the amount of aggregates, suggesting the significant contribution of Asp 48 to the reversible aggregation. To the best of our knowledge, this is the first report which provides the structural evidence for heavy metal‐induced multimerization of a protein.