Ashutosh Agrahari
Graduate Student
Purdue University
Talk Information
Peptide Synthesis and Innovation
16 June 2025, 04:55pm - 05:05pm, in the Pacific Jewel Ballroom
L19 - YI4 – Growth Mechanism of Coiled-Coil Peptide Nanocrystals and their Application for Intracellular Delivery of Proteins
Ashutosh Agrahari is a doctoral candidate in the Department of Chemistry at Purdue University, where he is engaged in advanced research within the Chmielewski Research Group. His academic journey commenced at the Indian Institute of Science Education and Research, IISER, Bhopal, where he earned a dual BS-MS degree in Chemistry. Currently, he is pursuing his Ph.D. at Purdue, with an expected completion in June 2026.
Research Focus
Mr. Agrahari's research interests lie at the intersection of chemical biology and biomaterials. His work involves the design and synthesis of novel macrocyclic peptides, aiming to enhance their membrane permeability and therapeutic potential. Through his research, he contributes to the development of next-generation peptide-based therapeutics.
Notable Publications
Sequential Oxidation of Sulfur Annulated Perylenediimide: An Efficient Strategy to Generate Ultra-Stable Radical Anions and Dianions, 2022.
Metal-Promoted Higher-Order Assembly of Disulfide-Stapled Helical Barrels, 2023.
Professional Affiliations
Mr. Agrahari is an active member of the Chmielewski Research Group at Purdue University. His collaborative work within this group contributes to the advancement of chemical biology and the development of innovative biomaterials.
Through his dedication to research and academic excellence, Ashutosh Agrahari is poised to make significant contributions to the field of chemistry, particularly in the development of peptide-based therapeutics.
Growth Mechanism of Coiled-Coil Peptide Nanocrystals and Their Application for Intracellular Delivery of Proteins
Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
Coiled-coil peptides have shown great promise as building blocks in developing hierarchical biomaterials. The GCN4 leucine zipper is one such motif that has previously been modified with the metal binding ligands, nitrilotriacetic acid and di-histidine at the N and C-terminus, respectively, to facilitate metal-promoted higher order assembly. The trimeric leucine zipper, p2L was reported to generate micron-scale hexagonal crystals with Zn(II) that encapsulate His-tagged proteins via His tag-metal interactions.1,2 However, their larger size limited their applicability for cellular delivery of protein cargos, resulting in the need for the development of nanoscale higher-order materials.
Here we present the formation of nanocrystals with p2L in the presence of Ni(II) that are about 250 μm. Transmission electron microscopy (TEM) and small/wide angle x-ray scattering showed high ordering in the open-face hexagonal packing of coiled-coils within the nanocrystals. Furthermore, crystal growth was found to be more ordered throughout the P3 face in the presence of sodium salts, showing the influence of salts in preventing weaker ionic interactions. Temperature-dependent crystal growth experiments resulted in wider crystalline discs at lower temperature (4 ºC), whereas elevated temperature at 37 ºC favored metal-ligand interactions over ionic interactions in the radial direction, leading to taller crystals.
After studies to probe the growth mechanism, the nanocrystals were utilized to incorporate His-tagged eGFP for intracellular delivery of the proteins. Confocal microscopy indicated that nanocrystals enter the cells via endocytosis and cellular accumulation was found to be concentration and time dependent.