Senissar M, Manav M C, Brodersen D E
Centre for Bacterial Stress Response and Persistence, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, Aarhus, 8000, Denmark.
Protein Sci. 2017 Aug;26(8):1474-1492. doi: 10.1002/pro.3193. Epub 2017 May 24.
The PIN (PilT N-terminus) domain is a compact RNA-binding protein domain present in all domains of life. This 120-residue domain consists of a central and parallel β sheet surrounded by α helices, which together organize 4-5 acidic residues in an active site that binds one or more divalent metal ions and in many cases has endoribonuclease activity. In bacteria and archaea, the PIN domain is primarily associated with toxin-antitoxin loci, consisting of a toxin (the PIN domain nuclease) and an antitoxin that inhibits the function of the toxin under normal growth conditions. During nutritional or antibiotic stress, the antitoxin is proteolytically degraded causing activation of the PIN domain toxin leading to a dramatic reprogramming of cellular metabolism to cope with the new situation. In eukaryotes, PIN domains are commonly found as parts of larger proteins and are involved in a range of processes involving RNA cleavage, including ribosomal RNA biogenesis and nonsense-mediated mRNA decay. In this review, we provide a comprehensive overview of the structural characteristics of the PIN domain and compare PIN domains from all domains of life in terms of structure, active site architecture, and activity.
PIN（PilT N端）结构域是一种存在于所有生命域中的紧凑RNA结合蛋白结构域。这个由120个氨基酸残基组成的结构域由一个中央平行β折叠和周围的α螺旋组成，它们共同在一个结合一个或多个二价金属离子的活性位点中组织4-5个酸性残基，并且在许多情况下具有核糖核酸内切酶活性。在细菌和古细菌中，PIN结构域主要与毒素-抗毒素基因座相关，该基因座由一种毒素（PIN结构域核酸酶）和一种在正常生长条件下抑制毒素功能的抗毒素组成。在营养或抗生素应激期间，抗毒素被蛋白水解降解，导致PIN结构域毒素激活，从而引发细胞代谢的剧烈重编程以应对新情况。在真核生物中，PIN结构域通常作为较大蛋白质的一部分被发现，并参与一系列涉及RNA切割的过程，包括核糖体RNA生物合成和无义介导的mRNA降解。在本综述中，我们全面概述了PIN结构域的结构特征，并从结构、活性位点结构和活性方面比较了所有生命域中的PIN结构域。
