Multi-omic based production strain improvement (MOBpsi) for bio-manufacturing of toxic chemicals.

Robust systematic approaches for the metabolic engineering of cell factories remain elusive. The available models for predicting phenotypical responses and mechanisms are incomplete, particularly within the context of compound toxicity that can be a significant impediment to achieving high yields of a target product. This study describes a Multi-Omic Based Production Strain Improvement (MOBpsi) strategy that is distinguished by integrated time-resolved systems analyses of fed-batch fermentations.

The Role of Lipid Chains as Determinants of Membrane Stability in the Presence of Styrene.

Biofermentative production of styrene from renewable carbon sources is crucially dependent on strain tolerance and viability at elevated styrene concentrations. Solvent-driven collapse of bacterial plasma membranes limits yields and is technologically restrictive. Styrene is a hydrophobic solvent that readily partitions into the membrane interior and alters membrane-chain order and packing.

Interactions of polymyxin B with lipopolysaccharide-containing membranes.

Bacterial resistance to antibiotics constantly remodels the battlefront between infections and antibiotic therapy. Polymyxin B, a cationic peptide with an anti-Gram-negative spectrum of activity is re-entering use as a last resort measure and as an adjuvant. We use fluorescence dequenching to investigate the role of the rough chemotype bacterial lipopolysaccharide from BL21 as a molecular facilitator of membrane disruption by LPS.

Solid state NMR of membrane proteins: methods and applications.

Membranes of cells are active barriers, in which membrane proteins perform essential remodelling, transport and recognition functions that are vital to cells. Membrane proteins are key regulatory components of cells and represent essential targets for the modulation of cell function and pharmacological intervention. However, novel folds, low molarity and the need for lipid membrane support present serious challenges to the characterisation of their structure and interactions.

Membrane Protein Structure Determination and Characterisation by Solution and Solid-State NMR.

Biological membranes define the interface of life and its basic unit, the cell. Membrane proteins play key roles in membrane functions, yet their structure and mechanisms remain poorly understood. Breakthroughs in crystallography and electron microscopy have invigorated structural analysis while failing to characterise key functional interactions with lipids, small molecules and membrane modulators, as well as their conformational polymorphism and dynamics.

Highly Efficient Transfer of 7TM Membrane Protein from Native Membrane to Covalently Circularized Nanodisc.

Incorporating membrane proteins into membrane mimicking systems is an essential process for biophysical studies and structure determination. Monodisperse lipid nanodiscs have been found to be a suitable tool, as they provide a near-native lipid bilayer environment. Recently, a covalently circularized nanodisc (cND) assembled with a membrane scaffold protein (MSP) in circular form, instead of conventional linear form, has emerged.

Optimization of the Production of Covalently Circularized Nanodiscs and Their Characterization in Physiological Conditions.

Lipid nanodiscs are widely used platforms for studying membrane proteins in a near-native environment. Lipid nanodiscs made with membrane scaffold proteins (MSPs) in the linear form have been well studied. Recently, a new kind of nanodisc made with MSPs in the circular form, referred to as covalently circularized nanodiscs (cNDs), has been reported to have some possible advantages in various applications.

Tuning the Photocycle Kinetics of Bacteriorhodopsin in Lipid Nanodiscs.

Monodisperse lipid nanodiscs are particularly suitable for characterizing membrane protein in near-native environment. To study the lipid-composition dependence of photocycle kinetics of bacteriorhodopsin (bR), transient absorption spectroscopy was utilized to monitor the evolution of the photocycle intermediates of bR reconstituted in nanodiscs composed of different ratios of the zwitterionic lipid (DMPC, dimyristoyl phosphatidylcholine; DOPC, dioleoyl phosphatidylcholine) to the negatively charged lipid (DOPG, dioleoyl phosphatidylglycerol; DMPG, dimyristoyl phosphatidylglycerol). The characterization of ion-exchange chromatography showed that the negative surface charge of nanodiscs increased as the content of DOPG or DMPG was increased.