"The recently discovered wax ester synthases (WS/DGATs) have demonstrated potential to catalyze production of biodiesel (microdiesel) by microbial systems. However, one inherent feature of WS/DGATs, their preference of long chain fatty alcohols as co-substrate, prevents efficient use of WS/DGATs for production of biodiesel. Future structure-guided protein engineering studies to increase the selectivity of WS/DGATs towards ethanol should facilitate de novo biodiesel production by more effective use of WS/DGATs in microbial systems such as bacteria, yeast or algae. However, structures and structure-function relationships of WS/DGATs or their close homologues are not known. Here, the researcher proposes for the first time, the X-ray crystallographic, structural, and biochemical studies of three WS/DGAT variants to be performed in order to obtain their high-resolution atomic structures and to determine their structure-function relationships. The crystal structures of WS/DGATs and subsequent biochemical studies will complete years of prior research by providing structural explanation for WS/DGATs’ relative disfavor of ethanol as co-substrate. Structures will pave the way for future studies to facilitate more efficient biodiesel production and also have potential applications in biosynthesis of tailor-made wax esters and other chemicals derived from petrochemicals. The proposed study, which is tied to the career integration of the researcher at the host institution as a faculty member, has great potential to produce significant scientific contribution and commercial benefits to European Research Area. Moreover, career integration of the researcher will be a catalyst for the introduction of education and research in macromolecular X-ray crystallography and structural biology to the target country. Therefore, the researcher seeks funding within the 7th Framework People Work Programme Marie Curie Actions Career Integration Grants to pay for some of the costs of the study."