Halobacterium halobium spheroplasts synthesize and accumulate a bacteriorhodopsin precursor. By labeling of the precursor with [35S]Met and [3H]Leu followed by Edman degradation, we have confirmed the previous conclusion from the DNA sequencing that the precursor contains 13 additional amino acids at the NH2 terminus of bacteriorhodopsin. Although not processed in the spheroplasts, it integrate...

Photosystem I from the cyanobacterium Synechocystis sp. PCC 6803 was examined using the chemical cross-linkers glutaraldehyde and N-ethyl-1-3-[3-(dimethylamino)propyl]carbodiimide to investigate the organization of the polypeptide subunits. Thylakoid membranes and photosystem I, which was isolated by Triton X-100 fractionation, were treated with cross-linking reagents and were resolved using a ...

Glycols, aldehydes, and acrylamide inhibit the in vitro formation of cold cataracts in calf lenses. The inhibition is reversed when the glycols or the acrylamide are diffused out of the lenses. The inhibition by aldehydes or polacrylamide is irreversible, suggesting that the crosslinking reagents may permanently modify lens structure to prevent the development of lens opacities due to a phase t...

This study concerns the preparation of reagents for identifying the somatic O antigens of Salmonella enteritidis. Coagglutination reagents (COAGs) with antibody fixed to killed and stabilized protein A-bearing staphylococci were prepared with antisera which were used for identifying the somatic O antigens of S. enteritidis by the slide agglutination test. The reactions of the COAGs were compare...

Derivatives of staphylococcal nuclease containing monoaminotyrosyl residues in position 85 or 115 were treated at pH 5 with two bifunctional reagents, p,p’-difkoro-m,m’dinitrodiphenylsulfone (F2DPS) and 1,5-difluoro-2,4-dinitrobenzene (F*DNB). Monofunctional reaction occurred exclusively at the aminotyrosyl residue, and there was no significant hydrolysis of the second fluorine atom. The excess...

Video techniques were used to record changes in motility of cells of Streptococcus sp. strain V4051 exposed to a variety of protein modification reagents. Starved cells were tethered to glass by a single flagellum, energized metabolically with glucose, or treated with valinomycin and energized artificially via shifts to media containing low concentrations of potassium ion. Experiments were devi...

50S ribosomal subunits were reacted with bis-(2-chloroethyl)methylamine, 2-iminothiolane or methyl p-azidophenyl acetimidate, and RNA-protein cross-link sites on the RNA were localised using our published procedures. The degree of precision with which these sites could be determined was variable, depending on the particular protein or RNA region concerned. The following positions in the 23S RNA...

Qp replicase is a complex of four nonidentical subunits readily dissociable into two subcomplexes: 30 S ribosomal protein Sl and the phage-coded polypeptide (Subunits I + II) and protein synthesis elongation factors EF-Tu and EF-Ts (Subunits III + IV). The affinity of the two subcomplexes for one another increases with increasing ionic strength. The enzyme is capable of initiation of RNA synthe...

Improving reagent performance in immunoassays both to enhance assay sensitivity and to minimize interference are ongoing challenges in clinical diagnostics. We describe herein the syntheses of a new class of hydrophilic reagents containing sulfobetaine zwitterions and their applications. These zwitterionic reagents are potentially useful for improving the properties of immunoassay reagents. We ...

DNA cross-linking reagents are frequently unusually cytotoxic, and many, including the nitrogen mustards, are potent chemotherapeutic agents, presumably because DNA cross-links effectively block DNA replication. Most of these reagents form both interand intrastrand DNA cross-links, but it is unknown which is more effective at blocking repli cation and why. To evaluate the role of interstrand cr...