Phase changing biomolecules are used by nature to perform remarkable functions in extreme extracellular environments, e.g., tying bacterial colonies together, protecting cells from water, and enabling disease-forming plaques to survive a host immune response. These materials operate in extreme environments through structured hydrogen bonds that define their fibrous state, providing robust strength while also displaying functional chemistries like those of natural proteins. One particular organism has effectively exploited these materials for survival: barnacles use amyloid-like materials to form the durable underwater bond they rely on to withstand a lifetime of dynamic wave-swept seashores and extreme marine environments.[1] In the barnacle adhesive, physical mechanisms such as delivery and curing arise from specialized proteins that assemble via non-covalent interactions, a process governed by unique patterns found in adhesive protein sequences.[2,3]
Self-organizing biomolecules are an ideal class of functional materials with which to develop underwater materials such as adhesives: they can be delivered as free proteins/precursors to the bonding site, triggered to polymerize and solidify on demand, and persist underwater as highly insoluble networks that resist biological and chemical degradation.[2,4] With inspiration from nature, we use combinatorial cell/cell-free synthesis methods and high throughput nanomaterials testing to develop a diverse new class of specialist underwater materials. Barnacles use an organized co-block arrangement of sequence domains to dictate material formation, cohesive strength, and adhesive bonding properties of larger protein components. This discovery has led us to develop a library of patterned sequence motifs capable of controlling the physical and chemical properties of underwater materials delivery, formation and function.
To exploit both the high strength and displayed protein chemistries of phase changing biomolecules, we are also developing de novo designed peptides which can augment synthetic materials with enzyme-like properties. Since our system acts as an artificial enzyme, chemical selectivity and catalytic turn-over can be tailored using a single molecular platform. The dense hydrogen bonded structure preserves enzyme function in extreme environments, enabling biological remediation and sensing materials to operate in harsh field environments.
Candidates should have experience in the following areas: materials formation and characterization (self-assembly, materials testing), peptide design (computational modeling, molecular dynamics, design rules), analytical biochemical methods, biophysical analysis (CD, FTIR, AFM, kinetic and thermodynamic characterization), and/or cell-based protein expression and purification.
[1] C.R. So, K.P. Fears, D.H. Leary, J. Scancella, Z. Wang, J. Liu, B. Orihuela, D. Rittschof, C. Spillmann, and K.J. Wahl, “Sequence basis of Barnacle Cement Nanostructure is Defined by Proteins with Silk Homology”, Scientific Reports 6, 36219, 2016.
[2] C.R. So, J. Liu, K.P. Fears, D.H. Leary, J.P. Golden, and K.J. Wahl, “Self-Assembly of Protein Nanofibrils Orchestrates Calcite Step Movement through Selective Nonchiral Interactions”, ACS Nano, 9, 5782-5791, 2015
[3] C.R. So, E.A. Yates, L.A. Estrella, K.P. Fears, A.M. Schenk, C.M. Yip and K.J. Wahl, “Molecular recognition of structures is key in the polymerization of patterned barnacle adhesive sequences”, ACS Nano, 13, 5172-5183, 2019
[4] C.R. So, Y. Hayamizu, H. Yazici, C. Gresswell, D. Khatayevich, C. Tamerler and M. Sarikaya, “Controlling Self-Assembly of Engineered Peptides on Graphite by Rational Mutation”, ACS Nano, 6, 1648-1656, 2012.
adhesive; bioinspired materials; biomimicry; peptide; self-assembly; synthetic biology; de novo design;