title: Structural basis of a ribozyme's thermostability: P1-L9 interdomain interaction in RNase P RNA.
abstract: For stability, many catalytic RNAs rely on long-range tertiary interactions, the precise role of each often being unclear. Here we demonstrate that one of the three interdomain architectural struts of RNase P RNA (P RNA) is the key to activity at higher temperatures: disrupting the P1-L9 helix-tetraloop interaction in P RNA of the thermophile Thermus thermophilus decreased activity at high temperatures in the RNA-alone reaction and at low Mg2+ concentrations in the holoenzyme reaction. Conversely, implanting the P1-P9 module of T. thermophilus in the P RNA from the mesophile Escherichia coli converted the latter RNA into a thermostable one. Moreover, replacing the E. coli P1-P9 elements with a pseudoknot module that mediates the homologous interaction in Mycoplasma P RNAs not only conferred thermostability upon E. coli P RNA but also increased its maximum turnover rate at 55 degrees C to the highest yet described for a P RNA ribozyme.
authors.affiliation: Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, D-35037 Marburg, Germany.
authors.forename: Michal
authors.initials: M
authors.lastname: Marszalkowski
authors.forename: Dagmar K
authors.initials: DK
authors.lastname: Willkomm
authors.forename: Roland K
authors.initials: RK
authors.lastname: Hartmann
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D008969:Molecular Sequence Data; D009174:Mycoplasma / Q000201:enzymology / Q000235:genetics; D009690:Nucleic Acid Conformation; D012329:RNA, Bacterial / Q000737:chemistry / Q000378:metabolism*; D016337:RNA, Catalytic / Q000737:chemistry / Q000378:metabolism*; D043262:Ribonuclease P / Q000235:genetics*; D016963:Thermus thermophilus / Q000201:enzymology / Q000235:genetics
chemical_list: D012329:RNA, Bacterial; D016337:RNA, Catalytic; D043262:Ribonuclease P