Zohreh Farahbakhsh

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In stoichiometric amounts, the spin label N-tempoyl-(p-chloromercuribenzamide) reacts rapidly with one cysteine residue in membrane-bound bovine rhodopsin. This residue is distinct from the two reactive cysteines previously used as attachment sites for spectroscopic labels, and is on the external surface of the protein near the cytoplasmic membrane/aqueous(More)
To identify the native ligands of tear lipocalins, tear proteins were separated by size exclusion chromatography and the lipid content in the major protein fractions identified. Lipids extracted from native tears and purified tear lipocalins comigrated with fatty acids, fatty alcohols, phospholipids, glycolipids, and cholesterol on thin layer chromatograms.(More)
Thirty consecutive single cysteine substitution mutants in the amino acids Q225-I256 of bovine rhodopsin have been prepared and modified with a sulfhydryl specific nitroxide reagent. This sequence includes the E-F interhelical loop, a transducin interaction site. The accessibilities of the attached nitroxides to collisions with hydrophilic and hydrophobic(More)
To probe proximity relationships between different amino acids in the interhelical loops in the cytoplasmic domain of rhodopsin, we are using a general approach in which two cysteine residues are introduced at different locations. Here we report on the characteristics of one such mutant that contains the naturally occurring cysteine 316 near the cytoplasmic(More)
Five mutations of rhodopsin have been produced, each of which contains a unique cysteine residue at positions 62, 65, 140, 240, or 316 in the cytoplasmic domain. The single reactive cysteines were derivatized with a sulfhydryl-specific nitroxide spin-label, and the electron paramagnetic resonance (EPR) spectra were analyzed in both lauryl maltoside and(More)
The ability of hormones to activate responses in a variety of tissues decreases with age. The mechanism(s) responsible for these alterations are unclear. We have confirmed that the ability of a beta-adrenergic receptor agonist to activate lipolysis in isolated rat adipocytes decreases with age. Maximum response to isoproterenol was greater in 2-mo-old rats(More)
alpha-Crystallin is a major protein of the vertebrate lens once thought to be highly specialized for conferring transparency. However, recent work has revealed a wide tissue distribution and a sequence homology to small heat shock proteins, suggesting a more general role for the protein. Like other molecular chaperons, alpha-crystallin is known to bind to(More)
A new method using lysophosphatide and acyl-CoA as detergents has been used to solubilize the rat brain opiate receptor. After solubilization, lysophosphatide and acyl-CoA can be almost completely removed by an enzymatic reaction that uses an acyltransferase from rat liver microsomes and reconstitutes the solubilized receptor in membranous vesicles.(More)
All 20 single cysteine substitution mutants in the sequence Y136-M155 of bovine rhodopsin have been prepared and modified with a sulfhydryl-specific nitroxide reagent. This sequence contains the C-D interhelical loop, a transducin interaction site. The accessibilities of the attached nitroxides to collisions with paramagnetic probes in solution were(More)