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S Brewer

Publications and source records attributed to S Brewer.

At least 19 recordsLinked to original sources
PubMed1996

Wealth and safety.

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Accidents, Occupational↗
PubMed1990

Structure and function of X-Pro dipeptide repeats in the TonB proteins of Salmonella typhimurium and Escherichia coli.

The TonB protein is required for several outer membrane transport processes in bacteria. A short 33-residue peptide segment of TonB has been studied by 1H and 13C nuclear magnetic resonance spectroscopy. The sequence of this peptide segment contains multiple Glu-Pro and Lys-Pro dipeptide repeats that maintain rigid, elongated structures and flank a short connecting segment that adopts a beta-strand configuration. This TonB peptide is shown to interact specifically with the FhuA protein, the outer membrane receptor for ferrichrome-iron, providing the first direct evidence that the TonB protein interacts with outer membrane receptors. Interaction with the FhuA protein involves the extended structural element containing positively charged Lys-Pro repeats, and suggests a functional role for this segment of the TonB protein. As TonB is anchored in the cytoplasmic membrane the protein must, uniquely, span the periplasm. These data, together with studies described in the accompanying paper, suggest a model by which TonB serves to transduce conformational information over extended distances, from the cytoplasmic membrane to the outer membrane.

Amino Acid Sequence↗
PubMed1985

The widespread distribution of alpha-N-trimethylalanine as the N-terminal amino acid of light chains from vertebrate striated muscle myosins.

Identical tripeptides of the sequence X-Pro-Lys, where X is an unknown blocking group, were isolated from trypsin digests of bovine cardiac alkali light chain and the LC2 light chain of rabbit fast muscle. Chemical, electrophoretic and 1H-NMR evidence characterized X as an unusual amino acid, alpha-N-trimethylalanine (Me3Ala), which was earlier reported as the N-terminal amino acid of the A1 alkali light chain of rabbit fast muscle [Henry et al. (1982) FEBS Lett. 144, 11-15]. The narrow line width and chemical shift position (delta = 3.23 ppm) of the--N+-(CH3) protons of Me3Ala made 1H-NMR spectroscopy a convenient method to search for this residue in other light chains. A survey of many different light chains showed that this signal was present in all vertebrate striated muscle light chains of the A1-type (LC1, 'essential' light chains) and LC2-type ('DTNB'-light chains, 'phosphorylatable' light chains) but was absent from all invertebrate muscle and vertebrate smooth muscle light chains tested. It was also absent from the vertebrate fast-muscle-specific A2-type (LC3) light chains. The spectral characteristics of these signals were consistent with their having arisen from the protons of an--N+-(CH3)3 grouping. Since no epsilon-trimethyllysine could be detected in acid hydrolysates of these proteins, it appears that Me3Ala is a general feature as the N-terminal amino acid in these light chains. 1H-NMR studies on bovine cardiac myosin subfragment 1 (S1) showed that the Me3Ala methyl proton signal was clearly visible and that the spectrum more closely resembled that of a rabbit S1 isoenzyme, S1(A1), than S1(A2), suggesting that the 40-residue N-terminal segment of the alkali light chain in cardiac S1 also possesses a high segmental mobility. Addition of actin caused the same gross changes to the cardiac S1 spectrum as noted earlier for rabbit S1(A1) [Prince et al. (1981) Eur. J. Biochem. 121, 213-219]. In particular, a marked reduction in the segmental mobility of the N-terminal region of the alkali light chain was noted, consistent with a direct interaction of this area with actin.

Alanine↗
PubMed1975

The nature of arterial healing following dextran treatment of experimental small artery trauma.

Vascular thrombosis is a major cause of morbidity and death. Because of the many variables involved with thrombosis in patients, major advances in treatment often depend upon design and study of adequate experimental models which provide a degree of control of the variables. Arterial trauma was produced in small femoral arteries 3 mm. or less in diameter by a standardized intimectomy technique. One group of animals was treated with an equal volume of saline and served as controls. Serial sections of blood vessels at graded time intervals from one hour to 90 days were studied. The damaged blood vessels of dextran-treated animals did not thrombose and provided an opportunity for studying the mechanism of healing in traumatized blood vessels which remained patent. The damaged blood vessels of saline-treated animals uniformly thrombosed and eventually healed for scar formation with evidences of attempts at recanalization. The blood vessels of dextran-treated animals remained open for as long as 90 days and were re-endothelialized and healed. What appears to be beginning re-endothelialization of blood vessels of dextran-treated animals was observed as early as 48 hours. In a model experimental setting, dextran has been shown to prevent thrombosis and permit healing in small arteries subjected to a standardized surgical trauma.

Animals↗
PubMedDate not supplied

Changing times.

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Humans↗