THE TRINUCLEAR COPPER CLUSTER IN MULTICOPPER OXIDASES

对漆酶和抗坏血酸氧化酶在3k ~ 300k范围内的Epr光谱进行了测量和模拟，结果表明，由于蛋白质构象的改变，2型铜的结构由低温四面体转变为高温四面体。在5k ~ 300k范围内对鱿鱼进行了测量，测定了3型铜之间的反铁磁相互作用的- 2j值，发现在室温下抗坏血酸氧化酶的三重态是不可忽略的。随着叠氮化物作用量的增加，对漆酶的squid、esr光谱和共振拉曼光谱的仔细检测表明，叠氮化物通过削弱三核中心的相互作用，以端对端方式与3型铜中的一种结合，最终通过从配位球中排出桥接氢氧化物来破坏相互作用。

EPR SPECTRA OF LACCASE AND ASCORBATE OXIDASE WERE MEASURED FROM 3 K TO 300 K AND WERE SIMULATED,SHOWING THAT THE STRUCTURE OF TYPE 2 COPPER CHANGES FROM TETRAGONAL AT LOW TENPERATURE TO TETRAHEDRAL AT HIGH TEMPERATURE BECAUSE OF THE PROTEIN CONFORMATION CHANGE.SQUID WAS ALSO MEASURED FROM 5 K TO 300 K AND THE - 2J VALUE OF THE ANTIFERROMAGNETIC INTERACTION BETWEEN TYPE 3 COPPERS WERE DETERMINED AND WAS FOUND THAT THE TRIPLET STATE IS NOT NEGLIGIBLE AT ROOM TEMPERATURE IN THE CASE OF ASCORBATE OXIDASE.THE CAREFUL INSPECTION OF SQUID,ESR SPECTRA AND RESONANCE RAMAN SPECTRA OF THE INCREASING AMOUNT OF AZIDE ACTION ON LACCASE INDICATED THAT AZIDE IS BOUND TO ONE OF TYPE 3 COPPERS WITH THE END-ON FASHION BY WEAKENING THE INTERACTION IN THE TRINUCLEAR CENTER AND FINALLY BREAKING THE INTERACTION BY EXPELLING THE BRIDGING HYDROXIDE FROM COORDINATION SPHERE.