Ribosome inactivating proteins (RIPs) are plant proteins with enzymatic activity identified as rRNA N-glycosidase (EC 3.2.2.22), which cleaves the N-glycosidic bond of a specific adenine on the ricin/sarcin region of rRNA, thus causing inhibition of protein synthesis ...
Ribosome inactivating proteins (RIPs) are plant proteins with enzymatic activity identified as rRNA N-glycosidase (EC 3.2.2.22), which cleaves the N-glycosidic bond of a specific adenine on the ricin/sarcin region of rRNA, thus causing inhibition of protein synthesis. They also depurinate extensively DNA and other polynucleotides. The three-dimensional structure of dianthin 30, a type 1 (single-chain) RIP of Dianthus caryophyllus (leaves), is now described at 1.4 angstroms, a resolution never achieved before for any RIP. The fold typical of RIPs is conserved, despite some differences in the loop regions. The general structure comparison by superimposed alpha-carbon (249 atoms) and the sequence alignment by structure for dianthin 30 and saporin-S6 give a root mean square deviation of 0.625 angstroms. Despite the differences reported for the biological activities of the two RIPs, their structures fit quite well and both show a protein segment containing strands beta7, beta8, and beta9 shorter than other RIPs. However, the surface electrostatic potential in the active site region neatly distinguishes dianthin 30 from saporin-S6. The possible relationship between the charge distribution and the behavior of the proteins toward different substrates is discussed.
Related Citations:
Crystallization and preliminary X-ray diffraction analysis of two ribosomes-inactivating
proteins: lychnin and dianthin 30 Fermani, S., Falini, G., Ripamonti, A., Bolognesi, A., Polito, L., Stirpe, F. (2003) Acta Crystallogr D Biol Crystallogr 59: 1227
Ribosome-inactivating proteins from plants Barbieri, L., Battelli, M.G., Stirpe, F. (1993) Biochim Biophys Acta 1154: 237
Dianthins, ribosome-damaging proteins with anti-viral properties from Dianthus caryophyllus L. (carnation) Stirpe, F., Williams, D.G., Onyon, L.G., Legg, R.F., Stevens, W.A. (1981) Biochem J 195: 399
Organizational Affiliation:
Dipartimento di Chimica G. Ciamician, Alma Mater Studiorum Universita' di Bologna, via Selmi 2, I-40126 Bologna, Italy.
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