Febs Letters

doi: 10.1016/0014-5793(86)81518-6pmid: N/A

Duncan, Thomas M.; Parsonage, Derek; Senior, Alan E.

doi: 10.1016/0014-5793(86)81519-8pmid: 2876918

We propose a working model for the tertiary structure of the nucleotide‐binding domain of the β‐subunit of E. coli F1‐ATPase, derived from secondary structure prediction and from comparison of the amino acid sequence with the sequences of other nucleotide‐binding proteins of known three‐dimensional structure. The model is consistent with previously published results of specific chemical modification studies and of analyses of mutations in the β‐subunit and its implications for subunit interactions and catalytic mechanism in F1‐ATPases are discussed.

Dalrymple, Brian

doi: 10.1016/0014-5793(86)81520-4pmid: 3021539

The IS30 transposase exhibits significant amino acid sequence homology to the phage Mu repressor c in the amino‐ and carboxy‐terminal regions of the proteins. The conserved sequences include the proposed Mu repressor DNA binding site, which is also related to the proposed Mu and D108 transposase DNA binding sites. The carboxy‐terminal homologies are characterised by two almost complete, and one partial, somewhat diverged amino acid sequence repeats. Only weak homologies to this domain are present in the Mu transposase (Mu A). Nevertheless, a clear link between an insertion sequence and a bacteriophage has been established.

Summers, L.J.; Blundell, T.L.; Gause, G.G.; Tomarev, S.I.

doi: 10.1016/0014-5793(86)81521-6pmid: 3770205

Molecular models for Rana γ‐1 and γ‐2 crystallins have been constructed using computer graphics on the basis of the protein primary structure derived from the complementary DNA sequence and the three‐dimensional structure of calf γ‐II crystallin that has been defined at high resolution by X‐ray analysis. The models show that the cores of the two domains are conserved as hydrophobic, with the polypeptide chain arranged as a four Greek‐key motif structure. Although many lysines replace arginines at equivalent positions in mammalian proteins, the Rana crystallins also have an extensive series of ion pairs on their surface; these are strongly implicated in their function as stable structural molecules, which are highly conserved in the evolution of the vertebrate eye lens.

Thurin, Jan; Thurin, Magdalena; Herlyn, Meenhard; Elder, David E.; Steplewski, Zenon; Clark, Wallace H.; Koprowski, Hilary

doi: 10.1016/0014-5793(86)81522-8pmid: 3533633

Gangliosides from cell cultures established from melanocytic lesions, representing different stages of melanoma tumor progression, were analyzed by chemical and immunological means on thin‐layer chromatograms. The GD2 ganglioside and N‐acetylgalactosaminyl transferase, which catalyzes the biosynthesis of GD2 from its precursor GD3, were detected in cultures established from advanced primary and metastatic melanomas, but not in cultures of normal melanocytes. Immunohistochemical studies on tissue sections from all progression stages confirmed GD2 expression only in these advanced lesions. A distinct biochemical event thus coincides with the onset of faster growth and acquisition of metastatic competence in human melanoma tumor progression.

Lindy, Seppo; Sorsa, Timo; Suomalainen, Kimmo; Turto, Heikki

doi: 10.1016/0014-5793(86)81523-Xpmid: 3021535

Gold sodium thiomalate, a drug used widely in the therapy of rheumatoid arthritis, was found to be an activator of latent human polymorphonuclear leukocyte collagenase. The activation was demonstrated by two distinct and independent collagenase assays: (i) by recording with a spectrophotometer at 227 nm the enzyme‐induced increase in ultraviolet difference absorbance of native type I collagen connected to the cleavage of collagen at 37°C[(1986) Eur. J. Biochem. 156, 1‐4] and (ii) by SDS‐polyacrylamide gel electrophoresis analysis of formation of specific products of collagen resulting from collagenase cleavage at 25°C. Activation of latent collagenase by gold sodium thiomalate appeared to be of the same magnitude as by the known activator phenylmercuric chloride.

Hoppe, U.; Hoppe, E.M.; Peskar, B.M.; Peskar, B.A.

doi: 10.1016/0014-5793(86)81524-1pmid: 3021536

A conjugate of leukotriene (LT) E4 and bovine serum albumin (BSA) was prepared by covalently linking the free amino group of the hapten to the protein using dimethyl pimelindiimidate (DMP) as coupling reagent. Anti‐LTE4 antibodies were raised in rabbits immunized with the conjugate. Binding of[3H]LTE4 to the antibodies is inhibited by 50% with 0.63 ng LTE4, while the relative cross‐reaction of LTC4 and LTD4 is 46.3% and 12.6%, respectively. Using the radioimmunoassay release of sulfidopeptide‐LT (SP‐LT) from rat gastric mucosa incubated in vitro was determined after quantitative enzymatic conversion of SP‐LT to LTE4. It could be demonstrated that this method is suitable for determination of SP‐LT in biological material.

Pérez-Ortin, Josh E.; Estruch, Francisco; Matallana, Emilia; Franco, Luis

doi: 10.1016/0014-5793(86)81525-3pmid: 3021537

A method, termed ‘sliding‐end‐labelling’, has been devised to avoid a frequent artifact in nucleosome positioning by indirect end labelling, namely the appearing of DNA fragments originated by two nuclease cuts, one of them lying within the region covered by the probe. The method is applied to the nucleosome positioning in the yeast SUC2 gene for invertase.

Rousset, Monique; Trugnan, Germain; Brun, Jean-Louis; Zweibaum, Alain

doi: 10.1016/0014-5793(86)81526-5pmid: 2876919

The biosynthesis and post‐translational processing of sucrase‐isomaltase and dipeptidylpeptidase IV were studied by L‐[35S]methionine labeling, immunoisolation with monoclonal antibodies and SDS‐PAGE in post‐confluent Caco‐2 cells treated with monensin (10 μM, 48 h). In addition to its classical effect on the post‐translational processing of both hydrolases, i.e. an inhibition of the conversion of the high‐mannose to the complex glycosylated form of the enzymes, monensin was found to have two other effects: a marked decrease of sucrase‐isomaltase expression, but not of dipeptidylpeptidase IV; an increased turnover of glucose, as substantiated by increased rates of glucose consumption and lactic acid production and a decreased glycogen content. Whether these two effects are related to the particular differentiation and metabolic status of Caco‐2 cells is discussed, as well as a possible role for the drug‐induced modifications of glucose turnover on the decreased expression of sucrase‐isomaltase.

Tsuda, Terutaka; Hamamori, Yasuo; Yamashita, Takayuki; Fukumoto, Yasuo; Takai, Yoshimi

doi: 10.1016/0014-5793(86)81527-7pmid: 3021538

In quiescent cultures of Swiss 3T3 cells, platelet‐derived growth factor or fibroblast growth factor known to induce both protein kinase C activation and Ca2+ mobilization raised c‐fos mRNA. This action of the growth factors was mimicked by the specific activators for protein kinase C, such as phorbol esters and a membrane‐permeable synthetic diacylglycerol, and also by the Ca2+ ionophores, such as A23187 and ionomycin. Prostaglandin E1 known to elevate cyclic AMP also raised c‐fos mRNA, and this action was mimicked by 8‐bromo‐cyclic AMP, dibutyryl cyclic AMP and forskolin. These results suggest that expression of the c‐fos gene is regulated by three different intracellular messenger systems, protein kinase C, Ca2+ and cyclic AMP, in Swiss 3T3 cells.