Why there are only 20 natural amino acids?
Can you make other non-natural amino acids? Design some new amino acids.
Yes, non-natural (unnatural) amino acids (UAAs) can be chemically synthesized or engineered into biological systems using synthetic biology tools. These UAAs expand the chemical and functional diversity of proteins, enabling applications in drug discovery, materials science, and biotechnology. Below are strategies and examples of designed UAAs aligned with Ralph Lauren’s innovation goals (e.g., sustainable materials, bio-based textiles).
If you make an alpha-helix using D-amino acids, what handedness (right or left) would you expect?
If you make an alpha-helix using D-amino acids, the helix will adopt a left-handed conformation.
Can you discover additional helices in proteins?
Proteins can form several types of helices beyond the canonical α-helix, each with distinct structural and functional roles.
Why most molecular helices are right-handed?
Most natural helices (e.g., α-helices in proteins, DNA) are right-handed due to the chirality of L-amino acids and evolutionary selection for stability. Right-handed helices minimize steric clashes between side chains and backbone atoms, favoring thermodynamically stable structures. This preference is reinforced by the planar geometry of peptide bonds and hydrogen-bonding patterns in proteins.
Why do beta-sheets tend to aggregate?
Beta-sheets aggregate because their exposed edge strands have hydrophobic residues and free hydrogen-bonding capacity. These edges interact with complementary strands on other beta-sheets, forming stable "cross-beta" spines. In diseases like Alzheimer’s, misfolded beta-sheets stack into amyloid fibrils due to this inherent aggregation propensity.
What is the driving force for b-sheet aggregation?
β-sheet aggregation is primarily driven by hydrophobic interactions between exposed nonpolar side chains and hydrogen bonding between aligned peptide backbones. These forces stabilize stacked β-strands, particularly in misfolded proteins, allowing them to form tightly packed, ordered aggregates like amyloid fibrils.
Why many amyloid diseases form b-sheet?
Amyloid diseases form β-sheet-rich aggregates because β-sheets enable stable, repetitive hydrogen bonding between aligned peptide backbones and hydrophobic interactions between exposed nonpolar side chains. This structural arrangement allows misfolded proteins (e.g., Aβ in Alzheimer’s) to assemble into tightly packed, protease-resistant fibrils that evade cellular clearance mechanisms. The cross-β architecture is particularly prone to propagation, driving pathological amyloid accumulation.
Can you use amyloid b-sheets as materials?
Yes, amyloid β-sheets are promising biomaterials due to their high mechanical strength, self-assembly, and chemical stability. Engineered amyloid fibrils are used in nanowires, biodegradable films, and sustainable textiles, though their pathogenicity must be mitigated via sequence design or chemical modification.