Silk Mass Photometry Paper Published in JPCL
“Distinct Dimerization Mechanisms in Silkworm and Spider Silk Proteins Revealed by Mass Photometry”
https://pubs.acs.org/doi/full/10.1021/acs.jpclett.5c02335
Led by our PhD students Hannah Johnson (our lab) and Herman Dhaliwal (Garmann Lab, SDSU) — equal contributors — with expert guidance from Prof. Rees Garmann. Our team shaped the overarching questions and provided the native silk dope samples, while the Garmann lab did the heavy lifting with the mass photometry experiments.
What we found: Using mass photometry (MP), we see dimers dominate in both systems, but they’re stabilized differently:
• 🐛 Silkworm fibroin dimers (~690 kDa) split to ~340 kDa with DTT → consistent with disulfide-linked H–H dimers.
• 🕷️ Spider MaSp dimers (~550 kDa) resist DTT → noncovalent stabilization, with evidence of MaSp1–MaSp2 heterodimers.
Together, this clarifies how early oligomerization differs across silks and establishes MP as a tool for tracking higher-order assembly under spinning-relevant conditions.
Huge thanks to everyone involved and DOD-AFOSR who funded the research! Convinced MP will play a major role in understanding silk formation when combined with NMR, SAXS, and modeling in an integrative structural biology framework.