Crystal structure of horseradish peroxidase C at 2.15 angstrom resolution
Crystal structure of horseradish peroxidase C at 2.15 angstrom resolution
复制标题
DOI：
10.1038/nsb1297-1032
复制
发表时间：
1997-12-01
期刊：
影响因子：
--
通讯作者：
Poulos, TL
中科院分区：
文献类型：
--
作者：
Gajhede, M;Schuller, DJ;Poulos, TL
辣根过氧化物酶同工酶C(HRPC)的晶体结构已分辨到2.15埃。III类过氧化物酶特有的一个重要特征是在螺旋F和G之间的HRPC中有34个残基的长插入。该区域定义了部分底物访问通道，不存在于I类和II类过氧化物酶典型的核心保守折叠中。HRPC和花生过氧化物酶(PNP)的比较表明，即使在III类中，该区域的结构也是高度可变的。对于HRPC类型的过氧化物酶，其特征是较大的FG插入(相对于PNP有7个残基)和较短的F‘螺旋，我们已经确定了与芳香族给体分子直接相互作用的关键残基。HRPC的独特之处在于具有三个外周Phe残基的环，142、68和179。这些东西守卫着裸露的虹膜边缘的入口处。我们预测，这个芳香区对于HRPC结合芳香底物的能力是重要的。
The crystal structure of horseradish peroxidase isozyme C (HRPC) has been solved to 2.15 Angstrom resolution. An important feature unique to the class III peroxidases is a long insertion, 34 residues in HRPC, between helices F and G. This region, which defines part of the substrate access channel, is not present in the core conserved fold typical of peroxidases from classes I and II. Comparison of HRPC and peanut peroxidase (PNP), the only other class III (higher plant) peroxidase for which an X-ray structure has been completed, reveals that the structure in this region is highly variable even within class III. For peroxidases of the HRPC type, characterized by a larger FG insertion (seven residues relative to PNP) and a shorter F' helix, we have identified the key residue involved in direct interactions with aromatic donor molecules. HRPC is unique in having a ring of three peripheral Phe residues, 142, 68 and 179. These guard the entrance to the exposed haem edge. We predict that this aromatic region is important for the ability of HRPC to bind aromatic substrates.