BPCPPDYSOE21 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 9: Focus Phase Separation in Biological Systems I (joint session BP/CPP)
CPP 9.2: Vortrag
Dienstag, 23. März 2021, 09:20–09:40, BPc
Quantitative phase microscopy enables precise and efficient determination of biomolecular condensate composition — •Patrick M McCall1,2, K Kim3,4, AW Fritsch1, JM Iglesias-Artola1, LM Jawerth1,2, J Wang1, M Ruer1, A Poznyakovskiy1, J Peychl1, J Guck3,4, S Alberti3, AA Hyman1, and J Brugués1,2 — 1MPI-CBG, Dresden — 2MPI-PKS, Dresden — 3TU Dresden — 4MPI Science of Light
Many cellular processes rely on condensed macromolecular phases termed biomolecular condensates. Despite progress in measurements and theoretical descriptions of several condensate properties, an understanding of their most basic feature, composition, remains elusive. Here we combined quantitative phase microscopy and sessile droplet physics to measure the shape and composition of individual model condensates. This technique requires 1000-fold less material than traditional approaches, achieves a precision of better than 2 %, and does not rely on fluorescent tags, which we show can significantly alter phase behavior. The protein concentrations measured in three model condensates span a broad range, from 80 to 500 mg/ml, pointing to a natural diversity in condensate composition specified by protein sequence. We report salt- and temperature-dependent binodals as well as time-resolved measurements revealing that PGL3 condensates undergo a contraction-like process during aging. This leads to doubling of the internal protein concentration coupled to condensate shrinkage. We anticipate that this new approach will enable understanding the physical properties of biomolecular condensates and their function.