Protein component of the ribozyme ribonuclease P alters substrate recognition by directly contacting precursor tRNA.
The protein component of ribonuclease P (RNase P) binds to the RNA subunit, forming a functional ribonucleoprotein complex in vivo and enhancing the affinity of the precursor tRNA (pre-tRNA) substrate. Photocrosslinking experiments with pre-tRNA bound to RNase P reconstituted with the protein component of Bacillus subtilis ribonuclease P (P protein) site specifically modified with a crosslinking reagent indicate that: (i) the central cleft of P protein directly interacts with the single-stranded 5' leader sequence of pre-tRNA, and (ii) the orientation and register of the pre-tRNA leader sequence in the central cleft places the protein component in close proximity to the active site. This unique mode of interaction suggests that the catalytic active site in RNase P occurs near the interface of RNA and protein. In contrast to other ribonucleoprotein complexes where the protein mainly stabilizes the active tertiary fold of the RNA, a critical function of the protein component of RNase P is to alter substrate specificity and enhance catalytic efficiency.
Niranjanakumari
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S
Department of Biochemistry, Box 3711, Duke University Medical Center, Durham, NC 27710, USA.
Stams
T
T
Crary
S M
SM
Christianson
D W
DW
Fierke
C A
CA
D019943:Amino Acid Substitution; D001483:Base Sequence; D020134:Catalytic Domain; D003198:Computer Simulation; D003545:Cysteine; D017931:DNA Primers; D004722:Endoribonucleases / Q000737:chemistry* / Q000378:metabolism*; D014644:Genetic Variation; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D016133:Polymerase Chain Reaction; D017433:Protein Structure, Secondary; D012322:RNA Precursors / Q000737:chemistry / Q000378:metabolism*; D016337:RNA, Catalytic / Q000737:chemistry* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D043262:Ribonuclease P; D012984:Software; D013379:Substrate Specificity
D017931:DNA Primers; D012322:RNA Precursors; D016337:RNA, Catalytic; D011994:Recombinant Proteins; D004722:Endoribonucleases; D043262:Ribonuclease P; D003545:Cysteine