Koster A J, Walz J, Lupas A, Baumeister W
Max-Planck-Institut für Biochemie, Martinsried, Germany.
Mol Biol Rep. 1995;21(1):11-20. doi: 10.1007/BF00990965.
The 26S proteasome is the central protease of the ubiquitin-dependent pathway of protein degradation. The molecule has a molecular mass of approximately 2000 kD and has a highly conserved structure in eukaryotes. The 26S proteasome is formed by a barrel-shaped 20S core complex and two polar 19S complexes. The 20S complex has C2 symmetry and is formed by four seven-membered rings of which the outer rings (alpha-type subunits) are rotated by 25.7 degrees relative to the inner rings while the inner rings (beta-type subunits) are in register. From a comparison of the activity and regulation of the 26S and 20S particles it can be deduced that the 20S particle contains the protease activity while the 19S complex contains isopeptidase, ATPase and protein unfolding activities. In this article we describe the structures of various proteasome complexes as determined by electron microscopy and discuss structural implications of their subunit sequences.
26S蛋白酶体是蛋白质降解的泛素依赖性途径的核心蛋白酶。该分子的分子量约为2000 kD，在真核生物中具有高度保守的结构。26S蛋白酶体由一个桶状的20S核心复合物和两个极性的19S复合物组成。20S复合物具有C2对称性，由四个七元环组成，其中外环（α型亚基）相对于内环旋转25.7度，而内环（β型亚基）对齐。通过比较26S和20S颗粒的活性和调节，可以推断20S颗粒含有蛋白酶活性，而19S复合物含有异肽酶、ATP酶和蛋白质解折叠活性。在本文中，我们描述了通过电子显微镜确定的各种蛋白酶体复合物的结构，并讨论了其亚基序列的结构含义。
