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Makoto Kimura and Yoshimitsu Kakuta, MICROORGANISMS IN SUSTAINABLE AGRICULTURE AND BIOTECHNOLOGY
:Structural Biology of the Ribonuclease P in the Hyperthermophilic Archaeon Pyrococcus horikoshii OT3, 487-508, 2012.04, Pyrococcus horikoshii OT3 is a hyperthermophilic archaeaon isolated from hydrothermal fluid. Because of their genetic features as well as hyperthermophilic properties, macromolecules produced by this thermophilic bacterium have served as an excellent model for structural biology. Ribonuclease P (RNase P) is a ribonucleoprotein complex involved in the processing of the 5′-leader sequence of precursor tRNA (pre-tRNA). We found that RNase P RNA (PhopRNA) and five proteins in P. horikoshii OT3 reconstituted RNase P activity that exhibited enzymatic properties like those of the authentic enzyme. A mutational analysis indicated that nucleotides A40, A41, and U44 in PhopRNA are crucial for catalysis, strongly suggesting that PhopRNA catalyzes the hydrolysis of pre-tRNA in approximately the same manner as eubacterial RNase P RNAs, even though it has no enzymatic activity in the absence of the proteins. The P. horikoshii RNase P proteins are predominantly involved in optimization of PhopRNA’s conformation, though individually they are dispensable for RNase P activity in vitro. This chapter summarizes structure-function relationships of the P. horikoshii RNase P subunits, including the high-resolution structural information that is currently available for the protein subunits.. |
