Kolkowska Paulina, Krzywoszynska Karolina, Potocki Slawomir, Chetana Parashurampura Renukaprasanna, Spodzieja Marta, Rodziewicz-Motowidlo Sylwia, Kozlowski Henryk
Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie St., Wroclaw, Poland.
Dalton Trans. 2015 Jun 7;44(21):9887-900. doi: 10.1039/c5dt01005e.
The zinc binding loop domain of the HypA protein of Helicobacter pylori consists of two CXXC motifs with flanking His residues. These motifs bind metal ions, and thus they are crucial for the functioning of the whole protein. The N-terminal site, where His is separated from CXXC by Ser residue is more effective in binding Zn(2+) and Ni(2+) ions than the C-terminal site, in which His is adjacent to the CXXC motif. Studies on various modifications of the peptide sequence within the Ac-ELECKDCSHVFKPNALDYGVCEKCHS-NH2 loop show the role of the residues in the linker between the CXXC motifs and the effect of the length of the linker on the stability of the complexes it forms with Zn(2+), Cd(2+) and Ni(2+) ions. The proline residue in the linker between the two CXXC binding sites plays a distinct role in the metal ion binding ability of the loop, lowering the efficacy of the metal ion coordination. The deletion of the aliphatic residues from the linker between the CXXC motifs remarkably improves the binding efficacy of the loop.
幽门螺杆菌HypA蛋白的锌结合环结构域由两个带有侧翼组氨酸残基的CXXC基序组成。这些基序结合金属离子，因此它们对整个蛋白质的功能至关重要。N端位点（组氨酸通过丝氨酸残基与CXXC隔开）比C端位点（组氨酸与CXXC基序相邻）更有效地结合Zn(2+)和Ni(2+)离子。对Ac-ELECKDCSHVFKPNALDYGVCEKCHS-NH2环内肽序列的各种修饰研究表明了CXXC基序之间连接子中残基的作用以及连接子长度对其与Zn(2+)、Cd(2+)和Ni(2+)离子形成的复合物稳定性的影响。两个CXXC结合位点之间连接子中的脯氨酸残基在环的金属离子结合能力中起独特作用，降低了金属离子配位的效率。从CXXC基序之间的连接子中删除脂肪族残基可显著提高环的结合效率。
