Intracytoplasmic membranes (ICMs) are a common structural element found in almost all methanotrophic bacteria. They house the particulate methane monooxygenase (pMMO), which is the initial enzyme in the metabolism of methane. ICMs provide an increased surface area for pMMO, however, the membrane's other physiological or functional roles remain elusive. In particular, if ICMs play a role of helping the cell capture or partition methane. We used a combination of theoretical and experimental methods to characterize methane solubility in lipid membranes and the effects of membrane composition. Molecular dynamics simulations showed that the presence of a hopanoid, such as bacteriohopanetetrol (HBHT), decreases the fluidity of the membrane. However, methane molecules permeabilize into the center of the membrane irrespective of the HBHT content. The simulations also revealed that methane significantly enhanced the fluidity of the bilayer in the presence of HBHT/cholesterol. To test this observation experimentally, we made lipid diffusion coefficient measurements in the model membranes in the presence of methane and bacteriohopanetetrol/cholesterol using (FCS). The <i>in vitro</i> measurements were consistent with the molecular dynamics simulations.

Visualizing the role of membranes in methanotrophic bacteria with computational methods and fluorescence microscopy

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.