2czw
From Proteopedia
Crystal structure analysis of protein component Ph1496p of P.horikoshii ribonuclease P
Structural highlights
Function[RL7A_PYRHO] Multifunctional RNA-binding protein that recognizes the K-turn motif in ribosomal RNA, box H/ACA, box C/D and box C'/D' sRNAs (By similarity). When added to reconstituted ribonuclease P (RNase P) it increases the optimum temperature to that of the partially purified enzyme and causes a 5-fold increase in apparent Vmax. Binds the RNase P catalytic RNA.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedRibonuclease P (RNase P) is a ribonucleoprotein complex involved in the processing of the 5' leader sequence of precursor tRNA. We previously found that the reconstituted particle (RP) composed of RNase P RNA and four proteins (Ph1481p, Ph1601p, Ph1771p, and Ph1877p) in the hyperthermophilic archaeon Pyrococcus horikoshii OT3 exhibited the RNase P activity, but had a lower optimal temperature (around at 55 degrees C), as compared with 70 degrees C of the authentic RNase P from P. horikoshii [Kouzuma et al., Biochem. Biophys. Res. Commun. 306 (2003) 666-673]. In the present study, we found that addition of a fifth protein Ph1496p, a putative ribosomal protein L7Ae, to RP specifically elevated the optimum temperature to about 70 degrees C comparable to that of the authentic RNase P. Characterization using gel shift assay and chemical probing localized Ph1496p binding sites on two stem-loop structures encompassing nucleotides A116-G201 and G229-C276 in P. horikoshii RNase P RNA. Moreover, the crystal structure of Ph1496p was determined at 2.0 A resolution by the molecular replacement method using ribosomal protein L7Ae from Haloarcula marismortui as a search model. Ph1496p comprises five alpha-helices and a four stranded beta-sheet. The beta-sheet is sandwiched by three helices (alpha1, alpha4, and alpha5) at one side and two helices (alpha2 and alpha3) at other side. The archaeal ribosomal protein L7Ae is known to be a triple functional protein, serving as a protein component in ribosome and ribonucleoprotein complexes, box C/D, and box H/ACA. Although we have at present no direct evidence that Ph1496p is a real protein component in the P. horikoshii RNase P, the present result may assign an RNase P protein to L7Ae as a fourth function. A fifth protein subunit Ph1496p elevates the optimum temperature for the ribonuclease P activity from Pyrococcus horikoshii OT3.,Fukuhara H, Kifusa M, Watanabe M, Terada A, Honda T, Numata T, Kakuta Y, Kimura M Biochem Biophys Res Commun. 2006 May 12;343(3):956-64. Epub 2006 Mar 15. PMID:16574071[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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