Graduate Students Mini Symposium II 2023

Program

13:15 h Nadya Abbood - AG Bode
"Type S NRPS as a Tool for the Rapid Construction of Engineered Non-Ribosomal Peptide Synthetases"

With the introduction of the SYNZIP (SZ) assisted reprogramming of NRPSs, we established a new engineering method that enables the generation of engineered NRPSs on a large scale. SZs are synthetic leucine zippers with an affinity less than 10 nm, which we attached to various NRPS building blocks, extracted from different biosynthetic gene cluster of the strains Photorhabdus, Xenorhabdus and Bacillus, generating a new synthetic type of NRPSs (type S NPRS). Bioengineering these giant machineries spur chances to access modified peptides with altered physiochemical properties or improved bioactivities.¹Microbial nonribosomal peptide synthetases (NRPS) are multi-modular enzymes that produce many important therapeutic drugs including antibiotics, anti-cancer or immunosuppressive agents.

13:45 h Stefano Lometto - MPRG Hochberg
"Evolution of a fiber-forming enzyme"

Previous investigations showed how a mitochondrial Citrate synthase (CS) in the unicellular eukaryote Tetrahyemna thermophila is capable of forming filamentous structures similar to intermediate cytoskeletal filaments. By using a combination of ancestral sequence reconstruction (ASR) and experimental biochemisrty we aim to elucidate the evolution and the mechanisms underpinning fiber formation. Furthermore, using in vivo confocal microscopy we determine weather such ordered complexity is a product of natural selection or neutral evolution.

14:15 h Lara Connolley - AG Murray
"Partition complex structure can arise from sliding and bridging of ParB dimers"

Chromosome segregation is vital for cell replication and in many bacteria is controlled by the ParABS system. A key part of this machinery is the association of ParB proteins to the parS-containing centromeric region to form the partition complex. Here, we use semi-flexible polymer simulations to show the recently discovered properties of ParB sliding and bridging can explain partition complex formation. We find that bridges can organise the DNA into either a globular state or hairpin and helical structures, depending on the bridge lifetime. We also show that ParB sliding can reproduce the experimentally measured binding profile of Caulobacter crescentus. Our model clarifies the mechanism of partition complex formation and predicts its fine structure.