Kielb Patrycja, Sezer Murat, Katz Sagie, Lopez Francesca, Schulz Christopher, Gorton Lo, Ludwig Roland, Wollenberger Ulla, Zebger Ingo, Weidinger Inez M
Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin (Germany).
Department of Biochemistry and Structural Biology, Lund University, PO Box 124, 221 00 Lund (Sweden).
Chemphyschem. 2015 Jun 22;16(9):1960-8. doi: 10.1002/cphc.201500112. Epub 2015 Apr 23.
Cellobiose dehydrogenase catalyzes the oxidation of various carbohydrates and is considered as a possible anode catalyst in biofuel cells. It has been shown that the catalytic performance of this enzyme immobilized on electrodes can be increased by presence of calcium ions. To get insight into the Ca(2+) -induced changes in the immobilized enzyme we employ surface-enhanced vibrational (SERR and SEIRA) spectroscopy together with electrochemistry. Upon addition of Ca(2+) ions electrochemical measurements show a shift of the catalytic turnover signal to more negative potentials while SERR measurements reveal an offset between the potential of heme reduction and catalytic current. Comparing SERR and SEIRA data we propose that binding of Ca(2+) to the heme induces protein reorientation in a way that the electron transfer pathway of the catalytic FAD center to the electrode can bypass the heme cofactor, resulting in catalytic activity at more negative potentials.
纤维二糖脱氢酶催化多种碳水化合物的氧化，被认为是生物燃料电池中一种可能的阳极催化剂。研究表明，固定在电极上的这种酶的催化性能可因钙离子的存在而提高。为深入了解钙离子诱导固定化酶发生的变化，我们采用表面增强振动光谱（表面增强拉曼散射和表面增强红外吸收光谱）并结合电化学方法进行研究。加入钙离子后，电化学测量表明催化周转信号向更负的电位移动，而表面增强拉曼散射测量揭示了血红素还原电位与催化电流之间的偏移。通过比较表面增强拉曼散射和表面增强红外吸收光谱数据，我们提出钙离子与血红素的结合会诱导蛋白质重新定向，使得催化黄素腺嘌呤二核苷酸中心到电极的电子传递途径能够绕过血红素辅因子，从而在更负的电位下产生催化活性。
