Ribosomal protein L7Ae is a subunit of archaeal RNase P.
To the mounting evidence of nonribosomal functions for ribosomal proteins, we now add L7Ae as a subunit of archaeal RNase P, a ribonucleoprotein (RNP) that catalyzes 5'-maturation of precursor tRNAs (pre-tRNAs). We first demonstrate that L7Ae coelutes with partially purified Methanococcus maripaludis (Mma) RNase P activity. After establishing in vitro reconstitution of the single RNA with four previously known protein subunits (POP5, RPP21, RPP29, and RPP30), we show that addition of L7Ae to this RNase P complex increases the optimal reaction temperature and k(cat)/K(m) (by approximately 360-fold) for pre-tRNA cleavage to those observed with partially purified native Mma RNase P. We identify in the Mma RNase P RNA a putative kink-turn (K-turn), the structural motif recognized by L7Ae. The large stimulatory effect of Mma L7Ae on RNase P activity decreases to <or= 4% of wild type upon mutating either the conserved nucleotides in this K-turn or amino acids in L7Ae shown to be essential for K-turn binding. The critical, multifunctional role of archaeal L7Ae in RNPs acting in tRNA processing (RNase P), RNA modification (H/ACA, C/D snoRNPs), and translation (ribosomes), especially by employing the same RNA-recognition surface, suggests coevolution of various translation-related functions, presumably to facilitate their coordinate regulation.
Cho
I-Ming
IM
Department of Biochemistry and Molecular Genetics, Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA.
Lai
Lien B
LB
Susanti
Dwi
D
Mukhopadhyay
Biswarup
B
Gopalan
Venkat
V
D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D015153:Blotting, Western; D002942:Circular Dichroism; D007700:Kinetics; D017017:Methanococcus / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012322:RNA Precursors / Q000378:metabolism; D043262:Ribonuclease P / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013696:Temperature
D019843:Archaeal Proteins; D021122:Protein Subunits; D012322:RNA Precursors; D012269:Ribosomal Proteins; D043262:Ribonuclease P