SummaryIt is now generally accepted that many of the physiological effects of alcohol consumption are a direct result of binding to specific sites in neuronal proteins such as ion channels or other components of neuronal signaling cascades. Binding to these targets generally occurs in water filled pockets and leads to alterations in protein structure and dynamics. However the precise interactions required to confer alcohol sensitivity to a particular protein remains undefined.Using information from the previously solved crystal structures of the Drosophila melanogaster protein LUSH in complexes with short chain alcohols, we have designed and tested the effects of specific amino acid substitutions on alcohol binding. These effects of these substitutions, specifically S52A, T57S and T57A were examined using a combination of molecular dynamics, X-ray crystallography, fluorescence spectroscopy and thermal unfolding. These studies reveal that the binding of ethanol is highly sensitive to small changes in the composition of the alcohol binding site. We find that T57 is the most critical reside for binding alcohols, the T57A substitution completely abolishes binding, while the T57S substitution differentially affects ethanol binding compared to longer chain alcohols. The additional requirement for a potential hydrogen bond acceptor at position 52 suggests that both the presence of multiple hydrogen bonding groups and the identity of the hydrogen bonding residue are critical for defining an ethanol binding site. These results provide new insight into the detailed chemistry of alcohol's interactions with proteins.

We describe a new X-linked syndrome of marked short stature, severe intellectual handicap and an unusual facial appearance. High resolution prometaphase banding showed affected males to have an X chromosome tandem duplication; their karyotypes were designated 46,dup(X) (q13.1-q21.1)Y. In carrier females the abnormal X chromosome was late replicating. To verify the duplication, gene dosage studies were performed using an enzyme assay and DNA techniques. Prenatal diagnosis is available for carrier females using chromosome analysis of amniocytes or chorionic villi.

We describe a family with a syndrome of mental retardation, dystonic movements of the hands and dysarthria inherited in an X-linked recessive pattern. DNA marker studies gave a maximum lod score of 2.11 at theta of 0.00 for DXS41 with a likely localization of the gene to Xpter----Xp21.

A genomic cosmid library was used to develop seven highly polymorphic microsatellite markers for the Mexican spotted owl (Strix occidentalis lucida). These are the first reported microsatellite markers derived from this species. The cloned and sequenced repeat motifs include a triplet repeat of (AAT)n, two tetranucleotide repeats of (GATA)n, a tetranucleotide repeat of (ATCC)n, a compound repeat of (GA)n(GATA)n and the two pentanucleotide repeats (AGAAT)n and (ATTTT)n. The microsatellites described represent six presumably independent loci with the two pentanucleotide repeats having originated from a single cosmid. Primer pairs allow locus‐specific amplification of each marker from Mexican spotted owl genomic DNA.

LUSH is an odorant binding protein expressed in the olfactory organs of Drosophila melanogaster that is required for the detection of alcohol in adult flies. Here we demonstrate that, in the absence of ligand, in vitro LUSH exists in a partial molten globule state. The presence of short-chain n-alcohols at pharmacologically relevant concentrations less than 50 mM shifts the conformational equilibrium to a more compact state that exhibits reduced binding of the fluorescent dye 1-anilino-8-naphthalenesulfonic acid. Equilibrium unfolding studies of LUSH-alcohol complexes reveal that, for a series of short-chain n-alcohols, each methylene group can contribute approximately 1 K cal mol(-1) to the overall stability of the protein-alcohol complex. Using NMR spectroscopy, we have identified the regions of LUSH that show increased conformational stability on binding alcohols. These residues primarily line the alcohol-binding pocket. The results presented here provide a direct measure of the degree of stability that alcohol imparts on LUSH. These observations may represent a model for how ethanol can stabilize alternative protein conformations in alcohol-sensitive human proteins and ultimately lead to the observed changes in higher order function throughout the central nervous system.