Crystal Structure of a Ribonuclease P Protein Ph1601p from Pyrococcus horikoshii OT3: An Archaeal Homologue of Human Nuclear Ribonuclease P Protein Rpp21
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- 作者：Yoshimitsu Kakuta ; Ikuko Ishimatsu ; Tomoyuki Numata ; Kazumi Kimura ; Min Yao ; Isao Tanaka ; and Makoto Kimura
- 刊名：Biochemistry
- 出版年：2005
- 出版时间：September 13, 2005
- 年：2005
- 卷：44
- 期：36
- 页码：12086 - 12093
- 全文大小：453K
- 年卷期：v.44,no.36(September 13, 2005)
- ISSN：1520-4995
文摘
Ribonuclease P (RNase P) is a ribonucleoprotein complex involved in the removal of 5' leadersequences from tRNA precursors (pre-tRNA). The human protein Rpp21 is essential for human RNase Pactivity in tRNA processing in vitro. The crystal structure of Ph1601p from the hyperthermophilic archaeonPyrococcus horikoshii OT3, the archaeal homologue of Rpp21, was determined using the multipleanomalous dispersion (MAD) method with the aid of anomalous scattering in zinc and selenium at 1.6 Åresolution. Ph1601p comprises an N-terminal domain (residues 1-55), a central linker domain (residues56-79), and a C-terminal domain (residues 80-120), forming an L-shaped structure. The N-terminaldomain consists of two long 
-helices, while the central and C-terminal domains fold in a zinc ribbondomain. The electrostatic potential representation indicates the presence of positively charged clustersalong the L arms, suggesting a possible role in RNA binding. A single zinc ion binds the well-orderedbinding site that consists of four Cys residues (Cys68, Cys71, Cys97, and Cys100) and appears to stabilizethe relative positions of the N- and C-domains. Mutations of Cys68 and Cys71 or Cys97 and Cys100 toSer destabilize the protein structure, which results in inactivation of the RNase P activity. In addition,site-directed mutagenesis suggests that Lys69 at the central loop and Arg86 and Arg105 at the zinc ribbondomain are strongly involved in the functional activity, while Arg22, Tyr44, Arg65, and Arg84 play amodest role in the activity.
-helices, while the central and C-terminal domains fold in a zinc ribbondomain. The electrostatic potential representation indicates the presence of positively charged clustersalong the L arms, suggesting a possible role in RNA binding. A single zinc ion binds the well-orderedbinding site that consists of four Cys residues (Cys68, Cys71, Cys97, and Cys100) and appears to stabilizethe relative positions of the N- and C-domains. Mutations of Cys68 and Cys71 or Cys97 and Cys100 toSer destabilize the protein structure, which results in inactivation of the RNase P activity. In addition,site-directed mutagenesis suggests that Lys69 at the central loop and Arg86 and Arg105 at the zinc ribbondomain are strongly involved in the functional activity, while Arg22, Tyr44, Arg65, and Arg84 play amodest role in the activity.