A cooperative model for receptor recognition and cell adhesion: evidence from the molecular packing in the 1.6-A crystal structure of the pheromone Er-1 from the ciliated protozoan Euplotes raikovi.

The crystal structure of the pheromone Er-1 from the unicellular eukaryotic organism Euplotes raikovi was determined at 1.6 A resolution and refined to a crystallographic R factor of 19.9%. In the tightly packed crystal, two extensive intermolecular helix-helix interactions arrange the Er-1 molecules into layers. Since the putative receptor of the pheromone is a membrane-bound protein, whose extracellular C-terminal domain is identical in amino acid sequence to the soluble pheromone, the interactions found in the crystal may mimic the pheromone-receptor interactions as they occur on a cell surface. Based on this, we propose a model for the interaction between soluble pheromone molecules and their receptors. In this model, strong pheromone-receptor binding emerges as a consequence of the cooperative utilization of several weak interactions. The model offers an explanation for the results of binding studies and may also explain the adhesion between cells that occurs during mating.

Helix packing of lactose permease in Escherichia coli studied by site-directed chemical cleavage.

Biotinylated lactose permease from Escherichia coli containing a single-cysteine residue at position 330 (helix X) or at position 147, 148, or 149 (helix V) was purified by avidin-affinity chromatography and derivatized with 5-(alpha-bromoacetamido)-1,10-phenanthroline-copper [OP(Cu)]. Studies with purified, OP(Cu)-labeled Leu-330 --> Cys permease in dodecyl-beta-D-maltopyranoside demonstrate that after incubation in the presence of ascorbate, cleavage products of approximately 19 and 6-8 kDa are observed on immunoblots with anti-C-terminal antibody. Remarkably, the same cleavage products are observed with permease embedded in the native membrane. Comparison with the C-terminal half of the permease expressed independently as a standard indicates that the 19-kDa product results from cleavage near the cytoplasmic end of helix VII, whereas the 6- to 8-kDa fragment probably results from fragmentation near the cytoplasmic end of helix XI. Results are entirely consistent with a tertiary-structure model of the C-terminal half of the permease derived from earlier site-directed fluorescence and site-directed mutagenesis studies. Similar studies with OP(Cu)-labeled Cys-148 permease exhibit cleavage products at approximately 19 kDa and at 15-16 kDa. The larger fragment probably reflects cleavage at a site near the cytoplasmic end of helix VII, whereas the 15- to 16-kDa fragment is consistent with cleavage near the cytoplasmic end of helix VIII. When OP(Cu) is moved 100 degrees to position 149 (Val-149 --> Cys permease), a single product is observed at 19 kDa, suggesting fragmentation at the cytoplasmic end of helix VII. However, when the reagent is moved 100 degrees in the other direction to position 147 (Gly-147 --> Cys permease), cleavage is not observed. The results suggest that helix V is in close proximity to helices VII and VIII with position 148 in the interface between the helices, position 149 facing helix VII, and position 147 facing the lipid bilayer.

Studies in the packing industry /

[no. 1] The chain store and the packing industry, by E. L. Rhoades.--[no. 2] The management of chain meat markets, by E. L. Rhoades.--[no. 3] Chain stores and the independent meat retailer, by E. L. Rhoades.--[no. 4] Advertising of meats by chain grocery companies, by E. L. Rhoades.--[no. 5] Consumption of meat and meat products, with particular reference fo price, by J. H. Cover.

A method of manure disposal for a beef packing operation : first interim technical report /

"Project 12060 EOF."

Fruit harvesting, storing, marketing; a practical guide to the picking, sorting, packing, storing, shipping, and marketing of fruit,

Mode of access: Internet.

Cornfield products : a little journey thru a modern packing plant.

Promotional literature for White Provision Co.

A comparative study of packing, transportation, and refrigeration costs of bushel baskets and wirebound boxes for transportation of peaches,

Mode of access: Internet.

The "protecto-foam" packing method.

1st prize.

The rapid pack method of packing fruit /

Mode of access: Internet.

Drugs--current good manufacturing practice in manufacture, processing, packing, or holding. : regulations under the Federal Food, Drug, and Cosmetic Act, Part 133, Title 21, Code of Federal Regulations. Part 191, Hazardous substances.

Mode of access: Internet.

Census of manufactures: ... Lumber, and timber products, planing mills, wooden packing boxes ...

At head of title: 1921- : Department of Commerce ... Bureau of the Census ...

The meat packing industry in America.

Mode of access: Internet.

Packing of cotton at gins for uniform density /

"August 1943."

The closest packing of spheres : a unifying basis for crystal structures /

"AES research and development report"--Cover.