Structure - Function Relationship of Poly(U) Polymerases
Final Report Abstract
We were successful in determining the three-dimensional structure of Cid1 from S. pombe in complex with various nucleotide triphosphates from which we derived insights on key features that determine base specificity. Additionally, we were able to perform a detailed kinetic characterization by which we revealed that the catalytic efficiency of Cid1’s poly(U)polymerization is 150-fold higher than for poly(A)polymerization. Additionally, we identified a conserved histidine residue which is important for uracil recognition and mutation to an asparagine residue rendered Cid1 not to discriminate UTP from ATP. Our work was timely at that time, which is reflected that simultaneously to our publication, similar structural reports on Cid1 were published. Unfortunately, all of our attempts at characterizing the poly(U)polymerase PUP-2 from C. elegans that was reported to specifically promotes uridylation of pre-let7a miRNA mediated by Lin-28 was unsuccessful as we failed to reproduce this interaction in vitro.
Publications
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(2012). Crystal structures of the Cid1 poly (U) polymerase reveal the mechanism for UTP selectivity. Nucleic Acids Res., 40(19): 9815-24
Lunde, B.M., Magler, I., Meinhart, A.
