Crowley Christopher S, Sawaya Michael R, Bobik Thomas A, Yeates Todd O
University of California Los Angeles Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA 90095, USA.
Structure. 2008 Sep 10;16(9):1324-32. doi: 10.1016/j.str.2008.05.013.
The Pdu microcompartment is a proteinaceous, subcellular structure that serves as an organelle for the metabolism of 1,2-propanediol in Salmonella enterica. It encapsulates several related enzymes within a shell composed of a few thousand protein subunits. Recent structural studies on the carboxysome, a related microcompartment involved in CO(2) fixation, have concluded that the major shell proteins from that microcompartment form hexamers that pack into layers comprising the facets of the shell. Here we report the crystal structure of PduU, a protein from the Pdu microcompartment, representing the first structure of a shell protein from a noncarboxysome microcompartment. Though PduU is a hexamer like other characterized shell proteins, it has undergone a circular permutation leading to dramatic differences in the hexamer pore. In view of the hypothesis that microcompartment metabolites diffuse across the outer shell through these pores, the unique structure of PduU suggests the possibility of a special functional role.
Pdu微区室是一种蛋白质亚细胞结构，在肠炎沙门氏菌中作为1,2 - 丙二醇代谢的细胞器。它在由数千个蛋白质亚基组成的外壳内包裹着几种相关酶。最近对羧酶体（一种参与二氧化碳固定的相关微区室）的结构研究得出结论，该微区室的主要外壳蛋白形成六聚体，这些六聚体堆积成构成外壳小面的层。在此，我们报告了PduU（一种来自Pdu微区室的蛋白质）的晶体结构，它代表了非羧酶体微区室外壳蛋白的首个结构。尽管PduU与其他已表征的外壳蛋白一样是六聚体，但它经历了一次环形排列，导致六聚体孔有显著差异。鉴于微区室代谢物通过这些孔扩散穿过外壳的假设，PduU的独特结构表明它可能具有特殊的功能作用。
