Generation and Computational Characterization of a Complex Staphylococcus aureus Lipid Bilayer.
Faramarz Joodaki1, Lenore M Martin2, Michael L Greenfield1
1Department of Chemical Engineering, University of Rhode Island, 360 Fascitelli Center for Advanced Engineering, Kingston, Rhode Island 02881, United States.
Langmuir : the ACS Journal of Surfaces and Colloids
|July 28, 2022
Summary
This study computationally models the Staphylococcus aureus cell membrane, revealing complex lipid structures and dynamics crucial for antibiotic resistance. The findings offer new insights into membrane properties beyond simpler models.
Area of Science:
- Biophysics
- Computational Biology
- Microbiology
Background:
- The cell membrane plays a vital role in Staphylococcus aureus antibiotic resistance.
- Understanding membrane structure and dynamics is key to developing new therapeutic strategies.
Purpose of the Study:
- To create a detailed molecular-scale computational model of the S. aureus lipid bilayer.
- To investigate the impact of diverse lipid compositions on membrane properties.
Main Methods:
- Developed a computational representation of the S. aureus lipid bilayer.
- Optimized phospholipid types and amounts using reverse Monte Carlo simulations based on literature data.
- Analyzed lipid bilayer thickness, area per headgroup, and density profiles (phosphorus, nitrogen, water, carbon).
Main Results:
- Modeled a bilayer with 19 phospholipid types, including branched saturated chains.
- Observed specific orientations of lysyl-phosphatidylglycerol (LPG) headgroups.
- Identified distinct ordering and mobility patterns in branched vs. unbranched lipid tails.
- Found that longer tails can span across leaflets and branching introduces disorder.
Conclusions:
- Complex lipid compositions significantly influence S. aureus membrane properties.
- Simulations provide insights not achievable with simpler, monodisperse lipid models.
- This detailed model advances understanding of membrane function in antibiotic resistance.
Related Concept Videos
01:35Asymmetric Lipid Bilayer
7.6K
Biological membranes show uneven distribution of different types of lipids in the inner and outer layers, resulting in transverse asymmetric membranes. The treatment of the erythrocyte membrane with the enzyme phospholipase confirmed the asymmetric nature of the lipid bilayer. The enzyme hydrolyzes lipids into fatty acids and hydrophilic groups. The phospholipase acts only on the outer layer of the membrane, while the inner layer remains intact. The phospholipase treatment resulted in 80%...
7.6K
01:28Assembly of the Lipid Bilayer in the ER
3.3K
Biological membranes are more than just a barrier separating cell cytoplasm from the outside environment. They are highly dynamic and help maintain the integrity and physiological stability of the cells as well as membrane-bound organelles. Membranes also play vital roles in cell-to-cell and intracellular communication.
A large chunk of any biological membrane is composed of phospholipids. These lipids have a heterogeneous distribution across different subcellular organelles and even between...
A large chunk of any biological membrane is composed of phospholipids. These lipids have a heterogeneous distribution across different subcellular organelles and even between...
3.3K
01:29Biosynthesis of Lipids
83
Microbial membranes exhibit remarkable diversity in lipid composition, reflecting evolutionary adaptations to various environmental conditions. The three domains of life—Bacteria, Archaea, and Eukarya—synthesize membrane lipids through distinct biosynthetic pathways, leading to fundamental structural differences that impact membrane stability, function, and adaptability.Fatty Acid-Based Lipids in Bacteria and EukaryaBacteria and eukaryotes share a common fatty acid biosynthesis...
83
01:19Fluid Mosaic Model
12.5K
Scientists identified the plasma membrane in the 1890s and its principal chemical components (lipids and proteins) by 1915. The model for plasma membrane structure, proposed in 1935 by Hugh Davson and James Danielli, was the first model to be widely accepted in the scientific community. The model was based on the plasma membrane's "railroad track" appearance in early electron micrographs. Davson and Danielli theorized that the plasma membrane's structure resembled a sandwich...
12.5K
01:19Formation of Lipopolysaccharides
91
Lipopolysaccharides (LPS) are crucial components of the outer membrane of Gram-negative bacteria, serving both structural and functional roles. It contributes to membrane stability and protects bacteria from host immune responses. LPS is composed of three major regions—lipid A, a core oligosaccharide, and an O antigen. The biosynthesis and assembly of LPS involve a highly coordinated set of enzymatic reactions and transport mechanisms. Additionally, LPS is recognized as an endotoxin,...
91
01:32Membrane Lipids
25.7K
Lipids are an essential component of all biological membranes. The average lipid content in mammalian membranes is 50%, though it can be as low as 20% in the inner mitochondrial membrane or as high as 80% in the myelin sheath present around the nerve cells.
Phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and sphingomyelin are the most common phospholipids present in mammalian membranes. At physiological pH, phosphatidylserine is negatively charged, while the other three...
Phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and sphingomyelin are the most common phospholipids present in mammalian membranes. At physiological pH, phosphatidylserine is negatively charged, while the other three...
25.7K