Thesis (Ph.D)--Chemistry and Biochemistry, Georgia Institute of Technology, 2010. / Committee Chair: El-Sayed, Mostafa; Committee Member: Perry, Joseph; Committee Member: Wang, Zhong; Committee Member: Whetten, Robert; Committee Member: Zhang, John. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Undergraduate honors paper--Mount Holyoke College, 2007. Program in Biochemistry. / Includes bibliographical references (leaves 107-108).

Translation initiation factor 5A (IF5A) is an essential, highly conserved protein found within all eukaryotic (eIF5A) and archaeal (aIF5A) cells. The IF5A protein is unique in that it contains the amino acid hypusine; a two-step post translational modification of a single, conserved lysine residue. Although hypusination of eIF5A is vital for eukaryotic cell viability, the primary role of the protein and its hypusine side chain remain a mystery. eIF5A, initially identified as a translation initiation factor, is not required for global protein synthesis leading to the prevailing proposal that eIF5A is purely involved in the translation of a select subset of mRNAs. Recently a number of mutational studies have focused on the conserved, hypusine-containing loop region of eIF5A where specific residues have been found to be essential for activity without affecting hypusination. It has been postulated that eIF5A exists as a dimer (40 kDa) under native conditions and that these residues may be at the interface of dimerisation. The aim of this research was therefore to conduct a mutational analysis of the loop region in support of this hypothesis. A functional analysis of the Saccharomyces cerevisiae eIF5A mutant proteins K48D, G50A, H52A and K56A revealed that these substitutions impaired growth to varying degrees in vivo with G50A and K48D mutant proteins displaying the most convincing defects. Gel filtration profiles gave unexpected results determining eIF5A mutant and wild type proteins to have a native molecular weight of 30 to 31 kDa, suggesting that the eIF5A oligomeric state may be transitory and subject to certain conditions. The inconclusive results obtained from using gel filtration studies led to an investigation into the feasibility of producing native, hypusinated peptides for future structural studies using nuclear magnetic resonance. Hypusinated and unhypusinated eIF5A were successfully separated into their domains making this a possibility. Finally, this study proposes a role for eIF5A in eukaryotic IRES-driven translation initiation.

Motivation: Understanding how nucleic acids interact is essential for understanding their function. Controlling these interactions, for example, can allow us to detect diseases and create new therapeutics. During quantitative reverse-transcription polymerase chain reaction (qRT-PCR) testing, having nucleic acids interact as designed is essential for ensuring accurate test results. Accurate testing is an important consideration during the detection of COVID-19, the disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Results: I introduced the program DinoKnot (Duplex Interaction of Nucleic acids with pseudoKnots) that follows the hierarchical folding hypothesis to predict the secondary structure of two interacting nucleic acid strands (DNA/RNA) of similar or different type. DinoKnot is the first program that utilizes stable stems in both strands as a guide to find the structure of their interaction. Using DinoKnot, I predicted the interaction structure between the SARS-CoV-2 genome and nine reverse primers from qRT-PCR primer-probe sets. I compared these results to an existing tool RNAcofold and highlighted an example to showcase DinoKnot’s ability to predict pseudoknotted structures. I investigated how mutations to the SARS-CoV-2 genome may affect the primer interaction and predicted three mutations that may prevent primer binding, reducing the ability for SARS-CoV-2 detection. Interaction structure results pre- dicted by DinoKnot that showed disruption of primer binding were consistent with a clinical example showing detection issues due to mutations. DinoKnot has the potential to screen new SARS-CoV-2 variants for possible detection issues and support existing applications involving DNA/RNA interactions, such as microRNA (miRNA) target site prediction, by adding structural considerations to the interaction to elicit functional information. / Graduate

The luminescence properties of Van Der Waals' dimers and clusters of pyrene and diazapyrene have been investigated. Excimers, dimeric species which are associative in an excited electronic state and dissociative in their ground state, have long been established and play an important role in many areas of photochemistry. My work here focuses on the luminescence and absorption properties of ground state dimers/aggregates, which are less understood, and allows further characterization of the ground state and excited state association of these aromatic molecules.

by Maoqi Feng. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2000. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

En la presente tesis doctoral se han preparado dos alquenos altamente piramidalizados tricíclicos que han sido atrapados en forma de aductos Dielsalder. En ausencia de dienos se obtienen los correspondientes dimeros ciclobutánicos que experimentan una retrocicloadición térmica (2 + 2) a dimeros diénicos. Por otro lado se han llevado a cabo varios intentos para sintetizar tetrasecododecaedradienos bien por la dimerización de un alqueno piramidalizado tetracíclico de 10 átomos de carbono, bien por el acoplamiento cruzado de dos alquenos piramidalizados, uno tricíclico de 18 átomos de carbono y otro pentacíclico de 12 átomos de carbono.Paralelamente a este trabajo sintético se ha realizado un estudio teórico utilizando métodos de mecánica molecular, semiempíricos y "ab inicio", de los alquenos piramidalizados descritos en la tesis, de los C-dimeros ciclobutánicos y de los dimeros diénicos preparados. En general los cálculos teóricos correlacionan bien con los datos experimentales de los que disponemos.

The scarcity of research about nitrogen containing heterocyclic discotic liquid crystal has made it an interesting subject for chemists. In this thesis, we will discuss the synthesis and properties of four kinds of new dimeric discotic liquid crystal in details. The first type of new dimeric discotic liquid crystals were synthesized based on a novel core structure, dibenzo[a,c]phenazine. All dimers linked by a hexyl-chain spacer exhibited columar phase. The range of mesomorphic temperature became wide as the chain length of spacer increased. Simultaneously, we also changed terminal chain length to investigate the influence on mesomorphic properties by attached terminal group. The second type of new dimeric discotic liquid crystals, which contained the dibenzoquinoxaline skeleton, didn¡¦t show the properties of mesomorphic phase due to the poverty of planality. The third type of molecules, which also have the dibenzoquinoxaline skeleton, were the banana-shaped discotic liquid crystals. We anticipated these dimeric molecules would demonstrate another special mesogenic phase. The last type of dimeric discotic liquid crystals were the extension of our previously research. These molecules, which comprised 5,6,11,12,17,18- hexaazatrinaphthylene skeleton, would be good candidates for using as a n-type material.

Thesis (Ph. D.)--University of Chicago, Department of Chemistry, 2002. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Title from PDF title page (viewed Feb. 4, 2010). Additional advisors: Subramaniam Ananthan, David E. Graves, Craig D. Smith, Sadanandan E. Velu. Includes bibliographical references.