Week 11 HW: hw-building-genomes
👩🦰Part A: The 1,536 Pixel Artwork Canvas | Collective Artwork
Reflections on the HTGAA 2026 Collaborative Community Bioart Project
1. My Contribution to the Project
For this collaborative bioart experiment, I made part of the DNA pattern on the bottom right plate, ensuring the engineering of the custom fragments aligned perfectly with the broader communal design layout.
2. What I Liked About the Project
What stood out to me most was the brilliant interdisciplinary intersection of molecular biology, genetic evolution, and creative visual art. It was incredibly fulfilling to see highly complex scientific concepts—such as mutation frequencies, targeted genetic modifications, and cellular growth—manifest as a physical, living art installation. The sense of shared ownership within the paper study group and the broader HTGAA community made tracking the plates’ development an engaging, collaborative journey.
3. Areas for Improvement Next Year
To make this collaborative art experiment even better for the next cohort, I would suggest the following enhancements:
- Streamlined Digital Alignment Mapping: Implement a shared, real-time digital layout grid (such as a collaborative web canvas or vector mapping tool) prior to plating. This would help remote nodes and individual contributors preview how their specific plates interconnect geometrically with neighboring sections, avoiding minor spatial misalignments at the edges of the final composite image.
- Standardized High-Resolution Progression Tracking: Establish a unified imaging protocol across all participating nodes. Providing identical camera calibration settings or background lighting rigs for the growth phases would yield highly consistent time-lapse documentation, capturing the true vibrant morphology of the living medium across the entire collective canvas.
👩🦰Part B: Cell-Free Protein Synthesis | Cell-Free Reagents
Cell-Free Protein Synthesis (CFPS) Reaction System Analysis
1. Description of Component Roles
- E. coli Lysate (BL21 (DE3) Star Lysate, includes T7 RNA Polymerase) Provides the essential molecular machinery for transcription and translation, including ribosomes, tRNAs, initiation/elongation factors, and the T7 RNA polymerase required to transcribe target genes from DNA templates.
- Salts/Buffer (Potassium Glutamate, HEPES-KOH pH 7.5, Magnesium Glutamate, Potassium phosphate monobasic/dibasic) Maintains a stable physiological pH and supplies critical ionic cofactors (K+ and Mg2+) required to stabilize mRNA structures, support ribosome assembly, and optimize enzymatic activities during protein synthesis.
- Energy / Nucleotide System (Ribose, Glucose, AMP, CMP, GMP, UMP, Guanine) Serves as the metabolic driving engine by providing raw building blocks for RNA synthesis and generating high-energy molecules (ATP and GTP) via endogenous glycolytic and oxidative pathways to power translation.
- Translation Mix (17 Amino Acid Mix, Tyrosine, Cysteine) Provides the complete pool of all 20 standard amino acid monomers required by ribosomes to polymerize and elongate the growing polypeptide chain into a functional protein.
- Additives (Nicotinamide) Acts as a metabolic stabilizer or cofactor precursor that helps maintain the recycling of essential electron carriers (like NAD+) and prevents the degradation of energetic components in the cell-free system.
- Backfill (Nuclease Free Water) Brings the overall reaction setup to its precise target volume while ensuring the complete absence of degrading nucleases that could compromise mRNA or DNA template integrity.
2. Main Differences Between the Master Mixes
The 1-hour optimized PEP-NTP master mix relies on pre-synthesized, high-energy nucleoside triphosphates (NTPs) directly coupled with Phosphoenolpyruvate (PEP) to instantly drive transcription and translation, making it rapid but prone to early phosphate accumulation and reaction exhaustion.
In contrast, the 20-hour NMP-Ribose-Glucose master mix uses lower-energy nucleoside monophosphates (NMPs), ribose, and glucose to fuel an economical, sustained system. This setup utilizes endogenous metabolic pathways within the lysate to slowly and continuously regenerate ATP and GTP over an extended duration, dramatically prolonging the reaction lifetime.
3. Bonus Question: How Transcription Occurs Without Free GMP
Transcription can still occur because the E. coli lysate contains active, endogenous salvage pathway enzymes (such as purine phosphoribosyltransferases).
These enzymes chemically rescue the free Guanine base by attaching it to a ribose-5-phosphate donor (generated via the system’s Ribose and energy components), successfully synthesizing GMP in situ. Once GMP is generated via this salvage mechanism, it is sequentially phosphorylated by native kinases into GDP and finally into GTP, providing the necessary nucleotide triphosphate required by T7 RNA Polymerase to transcribe RNA.
👩🦰Part C: Planning the Global Experiment | Cell-Free Master Mix Design
Biophysical Analysis and Master Mix Optimization for Cell-Free Fluorescent Art
1. Biophysical & Functional Properties Influencing Cell-Free Expression
sfGFP (Superfolder GFP)
- Property: Extremely rapid folding kinetics and high thermodynamic stability.
- Effect: Its robust folding mechanism allows sfGFP to mature efficiently in a wide range of cell-free reaction environments, making it less prone to aggregation even under crowded or sub-optimal translation conditions.
mRFP1 (Monomeric Red Fluorescent Protein 1)
- Property: Slow, oxygen-dependent chromophore maturation and susceptibility to premature photobleaching.
- Effect: Because cell-free systems have limited passive oxygen diffusion, mRFP1 often displays a pronounced lag in signal readout and lower overall fluorescence yield compared to newer red variants.
mKO2 (Monomeric Kusabira Orange 2)
- Property: High pH/acid sensitivity and narrow pKa profile (~5.5).
- Effect: As organic waste products and organic acids accumulate during extended cell-free metabolic shifts, a dropping reaction pH can drastically quench mKO2’s orange fluorescence readout.
mTurquoise2 (Cyan Fluorescent Protein)
- Property: Rigidified chromophore environment leading to an exceptionally high quantum yield.
- Effect: It produces a highly brilliant and distinct cyan readout in cell-free systems, provided that transcription and translation are carefully paced to prevent rapid protein misfolding.
mScarlet_I (High-Intensity Red Fluorescent Protein Variant)
- Property: Exceptional intrinsic brightness but highly rigidified structure with strict folding checkpoints.
- Effect: It delivers a vibrant red color that outperforms mRFP1, but it demands an optimized molecular chaperone or translation pacing environment within the master mix to achieve its native, correctly folded state.
Electra2 (Fast-Maturing Fluorescent Protein)
- Property: Ultra-fast, near-instantaneous chromophore cyclization and maturation kinetics.
- Effect: This enables Electra2 to serve as an excellent real-time reporter for cell-free system activity, providing immediate visual readout within the first hour of expression before energy substrates diminish.
2. Experimental Optimization Hypothesis for 36-Hour Incubation
Hypothesis Statement
To maximize the long-term fluorescence yield of mRFP1 (or alternatively mKO2) over an extended 36-hour incubation, adjusting the Buffer System (HEPES-KOH / Potassium Phosphate) and the Energy/Oxygen Diffusion architecture within the custom reagent supplements will significantly reduce chemical quenching and sustain expression.
Detailed Engineering Mechanism
- Target Protein: mRFP1 (and by extension mKO2)
- Adjusted Reagents: Increase HEPES-KOH (pH 7.5) by 15% in the custom supplement mix, introduce a steady-state oxygenation mechanism (or optimize surface-area-to-volume geometry), and augment the baseline Glucose/Ribose fuel source.
- Expected Effect: Elevating the HEPES-KOH buffer capacity directly counteracts the drop in pH caused by organic acid accumulation over 36 hours, preventing the acid-induced quenching of the fluorescent proteins. Concurrently, enhancing oxygen availability satisfies the strict oxygen dependence required for mRFP1 chromophore maturation, forcing a steady, sustained conversion into the active, fluorescent state across the complete 36-hour incubation window.
3. Preliminary Master Mix Formulation Framework
Based on the required total reaction layout of 20 μL per well, the following standard volumetric composition can be used as a foundation to plan your assigned artwork wells once you receive your allocation: