%0 Journal Article %J Cell Chem Biol %D 2021 %T Target identification for small-molecule discovery in the FOXO3a tumor-suppressor pathway using a biodiverse peptide library. %A Emery, Amy %A Hardwick, Bryn S %A Crooks, Alex T %A Milech, Nadia %A Watt, Paul M %A Mithra, Chandan %A Kumar, Vikrant %A Giridharan, Saranya %A Sadasivam, Gayathri %A Mathivanan, Subashini %A Sudhakar, Sneha %A Bairy, Sneha %A Bharatham, Kavitha %A Hurakadli, Manjunath A %A Prasad, Thazhe K %A Kamariah, Neelagandan %A Muellner, Markus %A Coelho, Miguel %A Torrance, Christopher J %A McKenzie, Grahame J %A Venkitaraman, Ashok R %X

Genetic screening technologies to identify and validate macromolecular interactions (MMIs) essential for complex pathways remain an important unmet need for systems biology and therapeutics development. Here, we use a library of peptides from diverse prokaryal genomes to screen MMIs promoting the nuclear relocalization of Forkhead Box O3 (FOXO3a), a tumor suppressor more frequently inactivated by post-translational modification than mutation. A hit peptide engages the 14-3-3 family of signal regulators through a phosphorylation-dependent interaction, modulates FOXO3a-mediated transcription, and suppresses cancer cell growth. In a crystal structure, the hit peptide occupies the phosphopeptide-binding groove of 14-3-3ε in a conformation distinct from its natural peptide substrates. A biophysical screen identifies drug-like small molecules that displace the hit peptide from 14-3-3ε, providing starting points for structure-guided development. Our findings exemplify "protein interference," an approach using evolutionarily diverse, natural peptides to rapidly identify, validate, and develop chemical probes against MMIs essential for complex cellular phenotypes.

%B Cell Chem Biol %8 2021 Jun 01 %G eng %R 10.1016/j.chembiol.2021.05.009 %0 Journal Article %J Microb Biotechnol %D 2018 %T Automation aided optimization of cloning, expression and purification of enzymes of the bacterial sialic acid catabolic and sialylation pathways enzymes for structural studies. %A Bairy, Sneha %A Gopalan, Lakshmi Narayanan %A Setty, Thanuja Gangi %A Srinivasachari, Sathya %A Manjunath, Lavanyaa %A Kumar, Jay Prakash %A Guntupalli, Sai R %A Bose, Sucharita %A Nayak, Vinod %A Ghosh, Swagatha %A Sathyanarayanan, Nitish %A Caing-Carlsson, Rhawnie %A Wahlgren, Weixiao Yuan %A Friemann, Rosmarie %A Ramaswamy, S %A Neerathilingam, Muniasamy %X

The process of obtaining a well-expressing, soluble and correctly folded constructs can be made easier and quicker by automating the optimization of cloning, expression and purification. While there are many semiautomated pipelines available for cloning, expression and purification, there is hardly any pipeline that involves complete automation. Here, we achieve complete automation of all the steps involved in cloning and in vivo expression screening. This is demonstrated using 18 genes involved in sialic acid catabolism and the surface sialylation pathway. Our main objective was to clone these genes into a His-tagged Gateway vector, followed by their small-scale expression optimization in vivo. The constructs that showed best soluble expression were then selected for purification studies and scaled up for crystallization studies. Our technique allowed us to quickly find conditions for producing significant quantities of soluble proteins in Escherichia coli, their large-scale purification and successful crystallization of a number of these proteins. The method can be implemented in other cases where one needs to screen a large number of constructs, clones and expression vectors for successful recombinant production of functional proteins.

%B Microb Biotechnol %V 11 %P 420-428 %8 2018 Mar %G eng %N 2 %R 10.1111/1751-7915.13041