jz8b03153_si_liveslides.zip (13.16 MB)
How Molecular Crowding Differs from Macromolecular Crowding: A Femtosecond Mid-Infrared Pump–Probe Study
media
posted on 2018-11-16, 19:18 authored by Pramod
Kumar Verma, Achintya Kundu, Minhaeng ChoCrowding is an inherent
property of living systems in which biochemical
processes occur in highly concentrated solutions of various finite-sized
species of both low (molecular crowding) and high (macromolecular
crowding) molecular weights. Is molecular crowding fundamentally different
from macromolecular crowding? To answer this question, we use a femtosecond
mid-infrared pump–probe technique with three vibrational probes
in molecular (diethylene glycol) and macromolecular (polyethylene
glycol) solutions. In less crowded media, both molecular and macromolecular
crowders fail to affect the dynamics of interstitial bulk-like water
molecules and those at the crowder/water interface. In highly crowded
media, interstitial water dynamics strongly depends on molecular crowding,
but macromolecular crowding does not alter the bulk-like hydration
dynamics and has a modest crowding effect on water at the crowder/water
interface. The results of this study provide a molecular level understanding
of the structural and dynamic changes to water and the water-mediated
cross-linking of crowders.