The interaction of ribosome inactivating proteins with P protein is a case of convergent evolution

LAPADULA W.J.; ZARATE JM; SANCHEZ-PUERTA M.V.; JURI AYUB M

San Juan

Congreso; 2ª reunión conjunta de Sociedades de Biología de la República Argentina; 2011

Ribosome inactivating proteins (RIPs) are N-glycodidases that depurinate a specific adenine residue in the conserved sarcin/ricin loop in subunit 28S of rRNA. This proteins has different specificity against eukaryotic and prokaryotic ribosome, and all of this can depurinate nude rRNA (without ribosomal protein), suggesting that different RIPs would interact with different proteins. The interaction with P protein is one of the most studied; some RIPs have been reported to interact with the C-terminal end of this, including TCS, Shiga like 1/2 (SLK 1/2), Maize RIP and ricin and the interaction sites of two of them (TCS and Maize RIP) have been mapped. In this work, we use molecular phylogeny to support the hypothesis that different RIPs have achieved the ability to interact with P protein independently throughout evolution, being a case of convergent evolution. We design tree with maximum likelihood and Bayesian method to explain this hypothesis and design an alignment where, we can observe that interaction motives are different and it are in different position along the sequences. Moreover after affinity testing we propose pulchellin like a new RIPs that has the ability to interact with P protein. For this reason recombinant pulchellin was expressed and purified and SLK 2 was cloned too, to try to map possibles sites interaction of these toxins with P protein.