Acute myeloid leukemia (AML) is a highly heterogeneous disorder that results from a block in the differentiation of hematopoietic progenitor cells along with uncontrolled proliferation. In approximately 60% of cases, specific recurrent chromosomal aberrations can be identified by modern cytogenetic techniques, and is an important indicator to classify patients into three prognostic categories: favorable, intermediate, and poor risk. Currently, favorable risk patients are usually treated with chemotherapy while poor risk patients receive allogeneic stem cell transplantation. However, the largest subgroup of AML patients (approximately 40%) has no identifiable cytogenetic abnormalities and is classified as intermediate risk. In this special subgroup of patients, a number of studies have demonstrated the relationship between different translocations involving the mixed lineage leukemia (MLL) gene and patient prognosis. The heterogeneity of MLL-rearranged AML is reflected by the identification of more than 70 different fusion partners of this gene and the panel is continuously increasing. The aim of this study is to develop a sensitive molecular profiling test for relevant risk stratification that can help in the decision of treatment and/or follow-up strategy.

abstract: This thesis focuses on serial crystallography studies with X-ray free electron lasers (XFEL) with a special emphasis on data analysis to investigate important processes in bioenergy conversion and medicinal applications. First, the work on photosynthesis focuses on time-resolved femtosecond crystallography studies of Photosystem II (PSII). The structural-dynamic studies of the water splitting reaction centering on PSII is a current hot topic of interest in the field, the goal of which is to capture snapshots of the structural changes during the Kok cycle. This thesis presents results from time-resolved serial femtosecond (fs) crystallography experiments (TR-SFX) where data sets are collected at room temperature from a stream of crystals that intersect with the ultrashort femtosecond X-ray pulses at an XFEL with the goal to obtain structural information from the transient state (S4) state of the cycle where the O=O bond is formed, and oxygen is released. The most current techniques available in SFX/TR-SFX to handle hundreds of millions of raw diffraction patterns are discussed, including selection of the best diffraction patterns, allowing for their indexing and further data processing. The results include two 4.0 Å resolution structures of the ground S1 state and triple excited S4 transient state. Second, this thesis reports on the first international XFEL user experiments in South Korea at the Pohang Accelerator Laboratory (PAL-XFEL). The usability of this new XFEL in a proof-of-principle experiment for the study of microcrystals of human taspase1 (an important cancer target) by SFX has been tested. The descriptions of experiments and discussions of specific data evaluation challenges of this project in light of the taspase1 crystals’ high anisotropy, which limited the resolution to 4.5 Å, are included in this report In summary, this thesis examines current techniques that are available in the SFX/TR-SFX domain to study crystal structures from microcrystals damage-free, with the future potential of making movies of biological processes. / Dissertation/Thesis / Masters Thesis Chemistry 2020