Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


McKenney_Thesis_2018.pdf (8.79 MB)

ETD Abstract Container

Abstract Header

Investigating the basis of tRNA editing and modification enzyme coactivation in Trypanosoma brucei.

McKenney, Katherine Mary
http://rave.ohiolink.edu/etdc/view?acc_num=osu152266963775877

Abstract Details

2018, Doctor of Philosophy, Ohio State University, Biochemistry Program, Ohio State.
In all domains of life, transfer RNAs (tRNAs) undergo many post-transcriptional modifications and editing events that fine-tune their structural and functional properties. These processing events can be indispensable for translation and consequently survival. In T. brucei, tRNAThr undergoes hydrolytic deamination from adenosine (A) to inosine (I) at position 34, which expands the decoding capacity of tRNAThr by permitting wobble base pairing with the third position of the codon. tRNAThr in T. brucei also undergoes cytosine (C) to uridine (U) editing at position 32 of the anticodon loop; both deamination events are uniquely catalyzed by the same enzyme, TbADAT2/3. In addition to editing at position 32, tRNAThr is further methylated at the same position, yielding 3-methylcytidine (m3C) or 3-methyluridine (m3U). Interestingly, in vitro assays have shown that the recombinant m3C methyltransferase (TbTrm140) methylates C32 of a synthetic tRNA substrate only when TbADAT2/3 is present in the reaction. Furthermore, m3C is further deaminated to form m3U, while also requiring the presence of both enzymes. We show that the TbADAT2/3 and TbTrm140 act synergistically whereby the deaminase enhances the affinity of the methyltransferase for its substrate and vice versa. We also observe that active site residues in each enzyme have negligible effects on binding synergy. While these enzymes interact directly, these assays suggest that the observed binding synergy results from tRNA binding via domains distal to their active sites. These observations were validated by determination of binding affinity from single-turnover kinetic assays. Overall, this data provides a rationale for the interaction and functional codependence of these proteins.
Juan Alfonzo, PhD (Advisor)
179 p.
Biochemistry
Trypanosoma brucei; tRNA; RNA editing; methylation

Recommended Citations

Citations

  • McKenney, K. M. (2018). Investigating the basis of tRNA editing and modification enzyme coactivation in Trypanosoma brucei. [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu152266963775877

    APA Style (7th edition)

  • McKenney, Katherine. Investigating the basis of tRNA editing and modification enzyme coactivation in Trypanosoma brucei. 2018. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu152266963775877.

    MLA Style (8th edition)

  • McKenney, Katherine. "Investigating the basis of tRNA editing and modification enzyme coactivation in Trypanosoma brucei." Doctoral dissertation, Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu152266963775877

    Chicago Manual of Style (17th edition)

osu152266963775877
607
© 2018, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.