1r6l
Crystal Structure Of The tRNA Processing Enzyme Rnase pH From Pseudomonas Aeruginosa
OverviewOverview
RNase PH is a phosphate-dependent exoribonuclease that catalyzes the removal of nucleotides at the 3' end of the tRNA precursor, leading to the release of nucleoside diphosphate, and generates the CCA end during the maturation process. The 1.9-A crystal structures of the apo and the phosphate-bound forms of RNase PH from Pseudomonas aeruginosa reveal a monomeric RNase PH with an alpha/beta-fold tightly associated into a hexameric ring structure in the form of a trimer of dimers. A five ion pair network, Glu-63-Arg-74-Asp-116-Arg-77-Asp-118 and an ion-pair Glu-26-Arg-69 that are positioned symmetrically in the trimerization interface play critical roles in the formation of a hexameric ring. Single or double mutations of Arg-69, Arg-74, or Arg-77 in these ion pairs leads to the dissociation of the RNase PH hexamer into dimers without perturbing the overall monomeric structure. The dissociated RNase PH dimer completely lost its binding affinity and catalytic activity against a precursor tRNA. Our structural and mutational analyses of RNase PH demonstrate that the hexameric ring formation is a critical feature for the function of members of the RNase PH family.
About this StructureAbout this Structure
1R6L is a Single protein structure of sequence from Pseudomonas aeruginosa. Full crystallographic information is available from OCA.
ReferenceReference
Probing the functional importance of the hexameric ring structure of RNase PH., Choi JM, Park EY, Kim JH, Chang SK, Cho Y, J Biol Chem. 2004 Jan 2;279(1):755-64. Epub 2003 Oct 22. PMID:14573594 Page seeded by OCA on Sat May 3 07:08:44 2008