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Biomedical subjects

T E Thompson

Publications and source records attributed to T E Thompson.

143 records · Page 8Linked to original sources
PubMedDate not supplied

Methods for dual, site-specific derivatization of bovine pancreatic trypsin inhibitor: trypsin protection of lysine-15 and attachment of fatty acids or hydrophobic peptides at the N-terminus.

To produce a series of model membrane proteins, bovine pancreatic trypsin inhibitor (BPTI) has been modified by specifically attaching reporter groups to Lys-15 and fatty acids or hydrophobic peptides at the N-terminus. Lys-15 of BPTI was protected by trypsin bound to BPTI, then O-methylisourea (OMIU) was used to guanidinate all unprotected lysines. The N-terminal amine was then reacted with several saturated fatty acid anhydrides from 8 to 18 carbons in length, or with an SMCC cross-linker. Cysteine-containing hydrophobic peptides, cleaved from resin in the presence of sodium dodecyl sulfate (SDS), were then attached to the protein via the N-terminal cross-linker. The methods described yield a unique, chemically modified protein which can carry site-specific modifications at two distinct residues. The resulting proteins are ideal for diffusional or partitioning studies on model and biological membranes.

Acylation↗
PubMedDate not supplied

Effects of domain structure on in-plane reactions and interactions.

The existence of an in-plane domain structure in biological membranes raises the question of the physiological function, if any, of this structure. One important function may be to enhance or limit the equilibrium poise and rates of in-plane reactions through control by the cell of the percolation properties of the domain system. At low average domain occupancy by reactants or interactants, which must be the case for most biological membrane components, moving the domain system from connection to disconnection has marked effects on the apparent equilibrium poise and the rates of membrane-confined reactions. This conclusion is based on computer modelling of the effects of disconnection/connection of nine types of bimolecular in-plane reactions. Using the phase structure and percolation properties of two-component, two-phase phospholipid bilayers, it is possible to examine experimentally homo- and heterodimerization reactions, and enzyme-catalysed reactions in-plane as well as the effects of a transmembrane peptide on these systems. These theoretical and experimental studies suggest that percolation effects may be physiologically important in biological membranes. Whether this is in fact the case remains to be demonstrated.

Biophysical Phenomena↗